chapter 9 & 10 &12 study guide
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Chapter 9 Joints Study Guide
STUDY CONCEPTS
Definitions: Articulation: The technical term for joint Arthrology: The study of joint structure, function and dysfunction. Amphiarthroses: Slightly moveable joints. Diarthroses: Freely moveable joints. Synostosis: immovable joints Suture: Articulate cranial bones non moveable in adults and slightly moveable in children, provide protection to the brain. Cornial suture, sagittal suture, squamous suture & Lambdoid suture are the four brain sutures. Fontanel: Un-ossified mesenchyme filled spaces between unfused bone, allow shifting during birth and brain growth. Syndesmoses: Greater distance between articulating surfaces with denser collagen than in a suture, slightly moveable. Gomphoses: A joint that anchors a tooth to its socket
.
Interosseous membrane: Where two bones are bound by a substantial sheet of dense irregular connective tissue, slightly moveable, most moveable of fibrous joints. Location: interosseous membranes unite radius to ulna & tibia to fibula. There are 4 interosseous Membranes (2) between radius & ulna (2) between tibia & fibula. Synchondroses: Bones are joined by hyaline cartilage, very little movement. Examples: Rib#1 and manubrium, Epiphyseal plate between epiphyses & diaphysis in adolescent long bones. As you age this becomes the Bony Joint. Symphyses; Bones joined by fibrocartilage. Amphiarthrosis provides cushioning and shock absorption, Ex. Pubic Symphysis, Intervertebral discs. Synovial joint: Occur where two bones are separated by a space called a joint cavity, the cavity contains friction reducing fluid called synovial fluid. Periosteum: C.T external surface of bones Joint capsule: Tissue that encloses joint cavity with two layers, outer fibrous capsule (CT continuous with the periosteum). Inner synovial membrane (areolar tissue that secrets synovial fluid) Synovial membrane: A thin barrier that lines the inside of some of your joints
. Articular cartilage: Cartilage found on the joint surfaces of the bones. Decreases friction, Hyaline Cartilage. Bursa: Saclike extension of joint capsule filled with synovial fluid, cushions and eases movement between adjacent muscles, where a tendon passes over a bone or between bone and skin. Tendon sheath: Elongated bursae that wrap around tendons
Lever: Provide mechanical advantages, allow increased amount of work without increasing the amount of energy used (convert a small amount of energy applied over a long distance to a large amount of energy applied to a small distance.) Two kinds of levers: Levers that increase the output of force Ex. Human moving a heavy object with a crowbar. Lever that moves objects further and faster Ex. Moving of a rowboat with a paddle- blade moves farther and faster than handle. Range of motion: Degrees of a circle through which a joint can move, determined by structure of articular surfaces, strength and tautness of capsule ligaments, and tendons. Stretching of ligaments increases range of motion. (classification of synovial joints) Action of muscles: Nervous system monitors joint position and muscle tone. (balance and posture.) Double jointed-ness: Doesn’t technically exist, it just means you have looser ligaments, tendons and joint capsules.
Uniaxial: Joint classification, the distal bone moves through 1 plane, flexion and extension. Supination & Pronation. Ex: Elbow Biaxal: Joint classification, the distal bone moves through 2 planes, Flexion & Extension, Adduction & Abduction. Ex: Wrist Triaxial: Joint classification, the distal bone moves through 3 planes, Flexion & Extension, Abduction & Adduction, Rotation Ex: Shoulder Anatomy or articular surfaces, how the bones interact 6 types: 1.Plane joint: Flat surfaces of bones articulate with each other by sliding/gliding movements. Biaxial or Triaxial. Ex. Ankle/Wrist joints. 2.Pivot joint: A circular projection on one bone articulates into a ring-like indentation on another bone. The first bone rotates on its longitudinal axis relative to another. Uniaxial, Supination & Pronation. Ex. Radioulnar joint. 3.Saddle joint: Saddle shaped surfaces of two bones articulate 4.Hinge joint: A linear convex surface on one bone articulates with a linear concave depression on another bone, Uniaxial. Cylindrical. Ex. Elbow & Knee. 5.Condyloid joint: An oval convex surface on one bone articulates with a depression on another bone, Biaxial. Ex. Radiocarpal and Metacarpophalangeal. 6.Ball-and-socket joint: A smooth hemispherical (circle) head on one bone articulates with cuplike circular depression on another bone, Triaxial. Ex. Shoulder & Hip. Arthritis: A broad term for pain and inflammation of joints, by age 80 nearly everyone has some level of joint degeneration. 2 classical types of osteoarthritis and rheumatoid arthritis. Rheumatoid arthritis: A autoimmune attack on joints, antibodies attack synovial membrane. Thickening of synovial membrane and over-production of synovial fluid. Creates pressure and pain, excess tissue leads to characteristic distortions. Treatment: sometimes remission occurs, standard treatment involves steroids and asprin to control inflammation, immune suppression drugs. Osteoarthritis: Results from years of joint wear and tear, articular cartilage softens and degenerates, synovial fluid production becomes limited, formation of bone spurs (abnormal extensions of bone into the joint cavity) on the exposed bone which causes pain. Crepitus: cracking sounds.
Arthroplasty: The surgical implantation of an artificial joint. Most replaced are the hips, knees, ankle's & shoulders. Faulty joint surfaces are removed and replaced with synonymous artificial components (titanium or stainless steel, cement and screws held in place.) Joint Classification
Know the characteristics and significances of freely movable and non-movable joints
.
Synarthroses
- immovable joints examples sutures in adult skull vertebrae and sacrum. Amphiarthroses- slightly moveable joints Ex. Pubic syntheses, Fibrous joints Diarthroses-
freely moveable joints Ex. Shoulder, Knee, Elbow and Hip Compare and contrast the three classifications of joints based on degree of movement. Synarthrosis –
immovable. Amphiarthrosis –
slightly moveable. Diarthrosis –
freely moveable. Bony, Fibrous, and Cartilaginous Joints
Describe bony joints. Give examples.
Synostosis occurs where the gap between two bones ossifies, 2 bones become 2. Synarthroses- Non moveable, examples: Frontal and mandibular bones in infants, Cranial sutures in elderly, 1
st
rib and sternum in elderly, adolescent epiphyses and diaphysis- epiphyseal line others: hip, sacrum and coccyx List and describe the three types of fibrous joints
. Give examples. Occur where collagen fibers span the space between bones, fibers emerge from one bone and penetrate other between the bones the collagen fibers are simply not calcified. Amphiarthroses- slightly moveable. Sutures- Non moveable in adults, slightly in children, articulate cranial bones provide protection to the brain. Ex. Cornial sutures, sagittal suture, squamous suture, lambdoid suture. Fontanels-
un ossified mesenchyme filled spaces between unfused bones, allow shifting of bones during early life and birth. Syndesmoses- Greater distance between articulating surfaces with denser collagen than in a suture. Slightly moveable Ex. Anterior tibiofibular ligament, Gomphoses (dentialveolar joint) periodontal ligament technically not an articulation because 2bones; tooth doesn’t equal bone. Interosseous membrane- where two bones are bound by a substantial sheet of dense irregular connective tissue. Slightly moveable, most moveable of fibrous joints, locations: interosseous membranes unite radius to ulna and tibia to fabula. We have 4 interosseous membranes (2) radius and ulna (2) tibia and fibula Compare and contrast interosseous membranes and syndesmoses.
Syndesmoses is a immovable joint in which bones are joined by a substantial sheet of dense irregular connective tissue called the interosseous membrane bother are slightly moveable however an example the syndesmoses is the Gomphoses which is technically not an articulation because it is not two bones it is a tooth and bone.
List and describe the two types of cartilaginous joints. Give examples. Synchondroses made of Hyaline cartilage and Symphyses made of fibrocartilage both allow some movement as they are amphiarthroses.
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Compare and contrast the two types of cartilaginous joints. Synchondroses made of Hyaline cartilage and Symphyses made of fibrocartilage both allow some movement as they are amphiarthroses. Synovial Joints
Describe the anatomy of a typical synovial joint. Be able to draw and label one with components. List and describe the 5 major synovial joint accessories. -Tendon: collagenous tissue that attaches bone to skeletal muscle -Ligament: collagenous tissue that attaches bone to bone. - Articular disc and menisci: cartilage extensions within the joint capsule medial and lateral meniscus (knee) that absorbs shock -Bursa: saclike extension of joint capsule filled with synovial fluid, cushion and ease movement between adjacent muscles, where a tendon passes over a bone or between bone and skin. -Tendon sheaths: elongated bursae that wrap around tendons Define lever. Explain why joints are levers. What are the two ways levers work?
Levers provide mechanical advantages, allowing increasing the amount of work without increasing the amount of energy used. Convert a small amount of energy applied over a long distance to a large amount of energy applied over a small distance.
Two kinds of levers; lever that increase output of force Ex. Human moving a heavy object with help of crowbar. Lever that moves objects further and faster. Ex. Blade moves farther and faster than handle.
Describe range of motion, and what determines range of motion of a specific joint. Range of motion is the degrees (of a circle) through which a joint can move. Determined by structure of articular surfaces, strength and tautness of capsule, ligaments and tendons. Identify examples of the synovial joint classification by axes of movement, including; (1) uniaxial, (2) biaxial, and (3) triaxial.
1.uniaxial; Flexion and extension Ex. Elbow 2. Flexion & extension, adduction & abduction Ex. Wrist 3. Rotation, Flexion & extension, abduction & adduction Ex. Shoulder List and describe (including structure, axes of rotation, and examples of) the 6 types of synovial joints based on anatomical structure.
1.Plane; flat surface of bones articulating with each other sliding and gliding, Biaxial or Triaxial Ex. Ankle or wrist joints. 2.Pivot circular projection on one bone articulates into a ring like indentation on another bone, the first bone rotates on its longitudinal axis relative to each other, Uniaxial, Supination and pronation. Ex. Radioulnar joint 3.saddle shaped surfaces of two bones articulated with each other, Biaxial Ex. Carpal and metacarpal in thumb 4.HInge; linear convex surface on one bone articulates with a linear concave depression on another bone, Uniaxial Ex. Elbow and knee 5.Condyloid; oval convex surface on one bone articulates with a depression on another bone, biaxial Ex. Radiocarpal and metacarpophalangeal 6.Ball-and-socket; smooth hemispherical head on one bone articulates with a cuplike depression on another bone, triaxial Ex. Hip and shoulder Compare and contrast saddle and pivot joints. Saddle and plane joints are found in your hands. The saddle joint makes your thumb opposable, while the plane joints allow your small wrist bones to shift in relation to one another. Compare and contrast hinge, condyloid, and ball-and-socket joints. hinge joints are uniaxial, ball and socket joints are triaxial and condyloids are biaxial. hinge joints have a linear convex surface on one bone that articulates with a concave depression of another bone, ball and socket joints are a smooth hemispherical head on a bone that articulates with a cup like depression on another bone, and condyloid joints are an oval convex surface on one bone that articulates with another oval depression on another bone. Aging of Joints and Arthroplasty
Compare and contrast the two types of arthritis. osteoarthritis - caused by mechanical wear and tear on joints / aging rheumatoid - autoimmune disease in which the body's own immune system attacks the body's joints. Both osteo- and rheumatoid arthritis increase with age.
Describe arthroplasty;
The surgical implantation of an artificial joint. Most replaced are the hips, knees, ankle's and shoulders. Faulty joint surfaces are removed and replaced with synonymous artificial components such as titanium or stainless steel and held in place with cement or screw's. Chapter 9 Joints Study Questions
Joints Classification
1.How could you tell if you were observing an articulation
? You are looking at a joint or any point at which bones meet, and they don’t have to be movable. 2.What would happen if a diarthrosis became a synarthrosis
? Diarthroses is a classification of joints that are freely moving, if they became a synarthrosis the joints would not be able to move. Bony, Fibrous, and Cartilaginous Joints
3.____ Influence of preventing collagen production on the formation of a bony joint
. Decrease, Collagen is the main compound in bones, and bony joints occur through the ossification of two bones. Without collagen, bones will not form, and without bones, bony joints cannot ossify. 4.What is the physiologic significance of sutures
? They allow shifting of bones during birth and early life Brain growth. 5.____ Influence of removing periodontal ligaments on the ability to run. No Change. Periodontal ligaments are in your gums and bind your teeth to your gums. Your mouth has nothing to do with running. 6.What would happen if the hyaline cartilage in synchondroses turned to bone
, in an epiphyseal plate
? If /when hyaline cartilage turns to bone, the epiphyseal plate then becomes the epiphyseal line. Once the cartilage turns to bone, the bone growth stops. 7.How could you tell the difference between a symphysis and a synchondrosis? In synchondrosis, the bones are joined by hyaline cartilage. Synchondroses are found in the epiphyseal plates of growing bones in children. In symphyses, hyaline cartilage covers the end of the bone but the connected by fibrocartilage. Symphyses are found at the joints between vertebrae. Synovial Joints
8.____ Influence of removing synovial fluid from a cartilaginous joint on the probability of proper joint function.
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NC. Synovial joints occur when two bones are separated by a joint cavity and that cavity is filled with synovial fluid for friction reduction and is diarthrosis. Cartilaginous joints occur where cartilage tissue spans the space between bones and is amphiarthrosis. 9.What is the physiologic significance of bursae
? Cushion and ease movement between adjacent muscles, where a tendon passes over bone, or between bone and skin. 10.What is the physiologic significance of joints acting as levers
? Allow increase amount of work without increasing the amount of energy used, increases output of force and move objects further and faster. 11.What is the physiological significance of being double jointed
? Looser ligaments, tendons and joint capsules increase flexibility and range of motion. 12.What would happen if a ball-and-socket joint was replaced with a hinge joint
? Ball and socket joints articulate with a cuplike circular depression on another bone, Hinge joints articulate with a linear concave depression on another bone, if replaced ball and socket joints would decrease the moving ability from triaxial to uniaxial. 13.How could you tell if you were observing a plane joint
? You would be observing a flat surface of bones that articulate with each other allowing sliding/ gliding movements such as the ankle/ wrist joints. 14.____ Influence of changing a hinge joint to a pivot joint on the number of planes the distal bone moves through. No Change
. Both the hinge joint and pivot joint are uniaxial, which means that that they are able to move through one plane. 15.How could you tell if an articulation was a condylar or saddle joint
? Condylar joints have an oval convex surface on one bone articulates with a depression on another bone in contrast to saddle joints that have two saddle shaped bones that articulate with each other. 16.How could you tell if a joint was a ball & socket, without using invasive techniques
?
By how many planes the joint can move through, ball and socket joints can move through all 3 planes because they
are triaxial. A ball and socket joint, like the hips and shoulders is created by a smooth hemispherical head on one bone articulating with a cup like depression on another bone.
Aging of Joints and Arthroplasty
17.____ Influence of osteoarthritis on the development of bone spurs
. Increase, years and years of joint wear and tear causes articular cartilage to soften and degenerate, synovial fluid production becomes limited resulting in bone spurs on the exposed bone. 18.What would happen if an individual with rheumatoid arthritis took immune suppression drugs
? The drugs can slow or stop the attack by disabling parts of the immune system however, they have an increased risk of illness and infection.
19.What would happen if an individual had to undergo arthroplasty
? Their faulty joint surfaces would be removed and replaced with synonymous artificial components.
Common joints to be replaced are the hip joints, the knee, ankle, or shoulder. The original joint would be replaced with synonymous artificial components such as titanium or stainless steel. Chapter 10 Muscular Tissue Study Guide
STUDY CONCEPTS
Be able to define the following Keywords: movement, contractility, extensibility, elasticity; muscle fiber, fascia,
perimysium, myoblast stem cells, myostatin, sarcolemma, transverse or T tubules, sarcoplasm, sarcomere,
sarcoplasmic reticulum, terminal cisternae, actin, myosin head binding site, myosin, troponin, tropomyosin,
myomesin, dystrophin, striations, A band, I band, H zone; anion, cation, somatic motor neuron, motor unit, synapse,
synaptic knob, acetylcholine (ACh), junctional folds, ACh receptors, acetylcholinesterase, ATP hydrolysis, cross-
bridge, power-stroke, sliding filament theory, length tension relationship, rigor mortis; muscle twitch, latent period,
wave summation, unfused tetanus, fused tetanus, motor unit recruitment, isometric contraction, isotonic contraction;
creatine kinase, anaerobic respiration, aerobic respiration, endurance, fatigue, lactic acid, oxygen debt; slow
oxidative fibers, fast glycolytic fibers; resistance training, endurance training, spasm, cramp, and myasthenia gravis.
Overview of Muscular Tissue
List and describe the three types and general functions of muscle tissue. 1.
Cardiac; pump blood continuously. 2.
Skeletal; movement, heat and posture. 3.
Smooth; peristalsis, pupil size, maintain blood pressure and flow
; in the lungs, it opens and closes airways; in the gastrointestinal system it plays a role in motility and nutrition collection; and yet it still serves a purpose in almost every other organ system as well. List and describe the 4 distinct properties of muscle cells. 1.Electrical excitability/ conductivity Responds to stimuli (chemical signals, stretch, electrical changes) by producing electrical signals- action potentials. 2.Contractility To shorten when stimulated 3.Extensibility= stretch Defines stretch, to stretch without being damaged. 4.Elasticity DOESNT = STRETCH To return to normal resting length and shape after contraction or extension. Not to be confused with elasticity and extensibility. Skeletal Muscle Tissue
Describe a skeletal muscle fiber. Skeletal muscle cell= skeletal muscle fiber 10-100 micrometers long, up to 30cm long
List and describe the connective tissues associated with a muscle. Fascia- connective tissue found between adjacent muscles and other organs blends into tendons which connect muscle to bone. Epimysium-Dense irregular CT that covers muscle belly; blends into fascia Perimysium- Thick layer of dense irregular CT that surrounds bundles of 10-100 muscle cells called fascicle nerves and vasculature.
Endomysium- Thin areolar CT around each muscle fiber capillaries and nerves with in fascicle.
Describe the process of embryonic muscle fiber development including the role of myostatin. Muscle fibers form from fusion of myoblast stem cells during embryonic development. Adult satellite cells can multiply to produce a small number of new muscle fibers. Before fusion, embryonic myoblast stem cells proliferate. Myostatin triggers transition from proliferation to fusion. Myostatin, embryonic protein that stops muscle stem cell proliferation and initiates fusion. If myostatin was inhibited, more stem cells proliferation; more stem cells before fusion; more muscle fibers after fusion; bigger adult muscles. Be able to draw a skeletal muscle fiber and its related components. Compare and contrast sarcoplasmic reticulum and T-tubules. The sarcoplasmic reticulum is a complex network of specialized smooth endoplasmic reticulum that is important in transmitting the electrical impulse as well as in the storage of calcium ions
. T-tubules (transverse tubules) are extensions of the cell membrane that penetrate the center of skeletal and cardiac muscle cells. Both aspects make up the muscle fibers and contribute to muscle contractions. Compare and contrast thin and thick filaments. Thin filaments are comprised mostly of the protein called actin whereas thick filaments are comprised mostly of the protein myosin. Both filaments interact with the sarcomere.
Compare and contrast regulatory and contractile proteins. Contractile proteins interact to shorten the sarcomere to generate force during a contraction. They are Myosin and Actin. Regulatory proteins act as the “switch”
by allowing the starting and stopping of contractions.They are Tropomyosin and Tropnin.Both reside in the Thin filament. List and describe the different contractile, regulatory, and structural proteins. Regulatory proteins that regulate the contractile proteins (Tropomyosin and Troponin).
”the switch” the allows the start and stop of contraction. Contractile Proteins Their physical interaction directly causes a contraction to occur. Proteins that interact to shorten the sarcomere to generate force during a contraction. (myosin and actin) Structural protein's function is alignment, stability, elasticity, and extensibility of myofibrils. Composed of; Titin “spring that allows muscle to return to natural size after stretching.”
The 3
rd
most plentiful protein in muscle (actin and myosin). Spans ½ of sarcomere anchoring the central M line to the Z-disk for alignment, anchoring and a muscle fibers elasticity. Alpha- Actin which forms the z-disk and anchor titin. Myomesin
Forms the M-Line and anchor titin and thick filament. Nebulin anchors the thin filament to Z-disks. Dystrophin anchors sarcomere to
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sarcolemma which is important in the transfer shortening of sarcome/myofibril to plasma membrane.
Describe the organization of the myofilaments into striations (Z disc, A band, I band, and H band, M line). Striations are the organization of thin and thick filaments in a sarcomere. -Z disk (zigzag shaped) End anchor made of alpha-actinin. -A band (dark band) spans the length of the thick filament, dark band where the thick filament is located, contains some areas where the thin and thick filament overlap. -H zone Center of A band where only thick filament is found, -M line center of H band made of myomesin -I band (only thin filament) light band where only the thin filament is located, bisected by the Z disk. Describe the changes in striations that occur as muscle fiber contracts. Detail how this relates to the orientation of the thin and thick filaments. - Sarcomere: shorten - A Band: stays the same - H Zone: shortens -I Band: shortens - Thin filament length: N/C - Thick filament length: N/C - Thin/thick filament overlap: increasing overlap -Thick filaments "walk" along thin filaments increasing the amt of overlap in the A band •This pulls the Z discs closer together -Z discs are connected to the sarcolemma More from this study set Movement -Can occur because of cells that are capable of shortening by converting the chemical energy of ATP into mechanical energy.
•Muscle Cells.
Contractility To shorten when stimulated Extensibility To stretch without being damaged Elasticity
To return to normal resting length & shape after contraction or extension Muscle fiber Skeletal muscle cell:
-10-100 mm in diameter
-Up to 30 cm long Contraction and Relaxation of Skeletal Muscle For a muscle cell to contract, the sarcomere must shorten. However, thick and thin filaments
—
the components of sarcomeres
—
do not shorten. Instead, they slide by one another, causing the sarcomere to shorten while the filaments remain the same length
.
List and describe the three main steps in muscle contraction. Describe a motor unit. A motor (output) neuron and the muscle fibers it innervates, muscle fibers of each unit are dispersed throughout a muscle. When one motor unit contracts it creates a small contraction, when a lot of motor units' contract is creates a big muscle contraction. There are 4 different levels of contraction are possible in this example: Compare and contrast large and small motor units Small motor units (2-20 muscle fibers per nerve fiber) are found in muscles that function for precision (eye m
uscles) Large motor units (100’s
-
1000’s of muscle fibers per nerve fiber) are found in muscles that function for strength control (gastrocnemius). Both types of motor units play a roll in exciting muscles and contribute of the muscles force.
Describe the neuromuscular junction. Be able to draw and label it. Compare and contrast junctional folds and synaptic end knobs Junctional folds- Folds in sarcolemma that increase surface area for ACh receptors Synaptic end knobs- • End of neuron fiber
• Contains vesicles filled with a chemical neurotransmitter Similar- they are both common neurons List and describe the four steps in the excitation process. 1.releases of ACh- nerve signal opens voltage-gated (neural) calcium channels in synaptic knob, calcium flows into (down concentration gradient) Calcium stimulates exocytosis of ACh into synaptic cleft. 2.Activation of ACh receptors ACh crosses the synaptic cleft and binds ACh receptors on sarcolemma of the muscle fiber. 3.production of a new electrical signal (action potential) binding of ACh to ACh receptors opens Na+ channels. Sodium flows into (down concentration gradient) The influx of Na+ increases the charge of the cell because it causes a new electrical signal to be initiated in the muscle fiber 4.termination of ACh activity. Acetylcholinesterase rapidly degrades ACh this is good because only have connection when needed.
List and describe the three steps in the excitation-contraction coupling process. 1. condcuting of electrical signal electrical signal spreads over sarcolemma and enters the T tubules.
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2. release of calcium from terminal cisternae; the electrical signal causes voltage-gated calcium channels in the terminal cisternae of the sarcoplasmic reticulum to open. Calcium flows out of the SR into the cytoplasm around the myofibril's calcium binds to troponin. 3. opening of myosin head binding sites; calcium binds to troponin and when something binds to protein it changes shape. Troponin changes shape which moves tropomyosin, movement of tropomyosin head binding sites on actin. Myosin head binding sites are now available to bind myosin.
List and describe the four steps in the contraction cycle. 1-ATP Hydrolysis (which releases energy); ATP that is bound to the myosin head hydrolyzes into ADP. Myosin heads hydrolyzed ATP and become reoriented and energized. 2-Myosin heads bind to actin forming cross bridges, the reoriented myosin head can now bound to exposed myosin head binding sites on actin forming a cross- bridge, half of the myosin heads on a thick filament are bound to a thin filament at one time this is a good thing because it prevents the loss of contractions because of elasticity 3-myosin cross bridges rotate toward the center of the sarcomere (power stroke), ADP is released causing the myosin head to return to original position toward the M-line without detaching from actin. This pulls the thin filament towards the M line s
hortening the sarcomere (arms on a rope) the filaments do not change length, thin and thick filaments do not become shorter just slide past each other (sliding filament theory) 4-As myosin heads bind ATP the cross bridges detach from actin, detachment of myosin from actin, a new ATP binds to the myosin causing disassociation from actin, the ATP causes extension to happen. ATP hydrolysis occurs (step 1) and myosin head reorients to bind to another binding site. Compare and contrast cross bridges and the power strokes. The myosin head forms a cross-bridge with actin, which initiates the power stroke
. During the power stroke, the myosin head bends with the release of ADP and inorganic phosphate. Another ATP binds to the myosin head, causing the cross-bridge to detach and returning myosin to the cocked configuration. Both the cross bridge and power stroke are essential in the contraction cycle.
Describe the events that must occur for muscle relaxation to occur. -Detachment of myosin from actin -Detachment of ca+ from troponin. -Active transport of calcium back into terminal cisternae which requires ATP. -Return of tropomyosin over myosin head binding sites. -Degradation of ACH by acetylcholinesterase -Muscle fiber returns to resting length because of elastic recoil of the titan protein Know the sequence of all molecular events in muscle contraction and relaxation.
Describe length-tension relationship, and why overly contracted or too stretched muscle fibers have decreased
function. Length tension relationship is the amount of tension generated depending on initial think and thin filament overlap. Optimum resting length produces greatest force when muscle contractions, maintained by nervous system (tone). The length-tension (L-T) relationship of muscle basically describes the amount of tension that is produced by a muscle as a feature of its length. Over stretched sarcomere resulted in a weak contraction because fewer cross bridges can form (smaller tug of war). Under stretched sarcomere extreme overlap between results in weak contraction because there is no more room.
Describe rigor mortis Stiffening of body 3-4 hours after death because of a deteriorating sarcoplasmic reticulum, if the SR deteriorates calcium is released into the cytosol and binds to troponin leading to contraction. After 24 hours fibers decay and rigor mortis is lost.
Behavior of Whole Muscles
Define a twitch contraction and list and describe the three phases of a twitch. Smallest imperceptible contraction of all the muscle fibers in a motor unit in response to a single action potential in its motor neuron 1.latent period; movement of a muscle electrical signal and release of ca2+ excitation- contraction coupling 2.contraction period; tension develops ca2+ binds to 3.relaxation period; active transport of ca2- and loss of tension ca returns to If a twitch is imperceptible, how can it be used to create perceptible contraction:
Understand how stimulation frequency relates to twitch strength.
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Describe the differences between a twitch, wave summation, unfused tetanus, and fused tetanus. Summation and Tetanus Contractions: Repeated twitch contractions, where the previous twitch has not relaxed completely are called a summation
. If the frequency of these contractions increases to the point where maximum tension is generated and no relaxation is observed, then the contraction is termed tetanus.
Compare and contrast isometric and isotonic muscle contractions. Isometric muscle contractions develop tension without changing length this is important in postural muscle functions and joint stabilization whereas isotonic muscle contractions are when the muscle length changes while contracting this is referred to as negative when working out. Both contractions support strength.
Muscle Metabolism
Compare and contrast the creatine phosphate system, anaerobic cellular respiration, and aerobic cellular respiration. Anaerobic cellular respiration is ATP production without oxygen, short term energy, provides about 2 minutes of energy Aerobic cellular respiration is ATP production with oxygen, long term energy, provides several minutes to hours of energy Creatine phosphate system is immediate energy, provides about 15 seconds of maximal contraction
Describe the sources of ATP for banked, immediate-, short-, and long-term energy needs during muscle activity. Banked: ATP already present in cell Immediate: ATP is generated using creatine phosphate system Short-term: ATP is generated using anaerobic cellular respiration Long-term: ATP is generated using aerobic cellular respiration
Compare and contrast endurance and fatigue.
Describe oxygen debt. Oxygen debt is the oxygen required (after vigorous exercise, using up the oxygen faster than it can be breathed in) to oxidize lactic acid, created from anaerobic cellular respiration.
Types of Skeletal Muscle Fibers
List and describe the three different varieties of muscle fiber. The three types of muscle fiber are slow oxidative (SO), fast oxidative (FO) and fast glycolytic (FG). SO fibers use aerobic metabolism to produce low power contractions over long periods and are slow to fatigue. FO fibers use aerobic metabolism to produce ATP but produce higher tension contractions than SO fibers. FG fibers use anaerobic metabolism to produce powerful, high-tension contractions but fatigue quickly.
Strength and Disorders
Compare and contrast resistance and endurance training. endurance training facilitates aerobic processes, whereas resistance training increases muscular strength and anaerobic power
. Both resistance and endurance training help people stay younger for longer, fight diabetes, increase muscle mass, lower blood pressure, reduce risk factors for cardiovascular disease (CAD), and keep the brain healthy, avoiding many neurological disorders and cognitive dysfunctionalities such as dementia
Compare and contrast muscular dystrophy and myasthenia gravis. STUDY QUESTIONS
Overview of Muscular Tissue
1. How could you tell if a muscle was a skeletal muscle
? The muscle is attached to the bone, it appears to be striated and multi-nucleated with parallel fibers and is around 10-100μm in diameter and up to 30cm long. Its function is to aid in movement, heat production and posture.
2. ____ Influence of destroying a muscle's elasticity characteristic on its function. Decrease, Elasticity gives the ability of muscular tissue to return to its original shape after contraction or extension. So, without elasticity the muscle would be nonfunctional because it is unable to return to its original shape.
Skeletal Muscle Tissue
3. How can you tell the difference between a skeletal muscle cell and a skeletal muscle fiber
? They are the same thing. 4. How could you tell how many cells fused to form a muscle fiber?
5. What is the physiologic significance of myostatin? Myostatin is an embryonic protein that stops myoblast stem cell proliferation and triggers fusion. Without Myostatin or late deployment of it, would result in more myoblast stem cell proliferation, which would cause there to be more myoblast stem cells before fusion, therefore more muscle fibers after fusion, then after fusion would result in bigger muscles. 6. What is the physiologic significance of T-tubules? In cardiomyocytes, invaginations of the sarcolemmal membrane called t-tubules are critically important for triggering contraction by excitation-contraction (EC) coupling 7. ____ Influence of removing terminal cisternae from a muscle fiber on its function
D. Terminal cisternae are sacs at the end of the smooth ER that serve as calcium reserves. Without these terminal cisternae calcium cannot be released when needed and muscle function will see a decline. Ca++ cannot be removed from the muscle cells, leading to tetany/permanent contraction. 8. What is the physiologic significance of myosin heads? In addition to binding actin, the myosin heads bind and hydrolyze ATP, which provides the energy to drive filament sliding. This translation of chemical energy to movement is mediated by changes in the shape of myosin resulting from ATP binding.
9. What is the physiologic significance of the actin myosin head binding site? Actin has receptors for myosin heads called myosin head binding sites where myosin heads bind to actin and facilitate muscle contraction. Tropomyosin molecules cover the myosin head binding sites and a troponin molecule sits on top of each tropomyosin molecule. Calcium binds to troponin, changing its shape (when a protein binds to something, it changes shape) which then causes tropomyosin to change shape, allowing the myosin head binding sites on actin to bind myosin. 10. What is the physiologic significance of the H-band?
Also known as transverse tubules, are tunnel like infoldings of sarcolemma that are important to carry electrical currents to the cell's interior to stimulate contractions. Also terminal cisternae are located next to T-tubules.
11. How could you tell if a muscle fiber had both thick and thin filaments, histologically? In each sarcomere, the broad band which appears dark in standard histological procedures is called the A-band. This band indicates the location of thick filaments (myosin); it is darkest where thick and thin filaments overlap
. The broad light band between the dark bands is the I-band. 12. What would happen if all dystrophin was removed from an individual’s muscle fibers?
Sarcomere would not be anchored to the sarcolemma. Myofibril would contract in plasma membrane. Tissue would become fibrotic leading to muscular dystrophy.
13. ____ Influence of muscle contraction on the size of the thin filament. No Changes When muscle contraction happens, the thin and thick filaments slide past each other, causing the sarcomere to shorten. The overlap between these filaments is an important factor to determinate the contractile force. However, the lengths of the thin and thick filaments do not change.
Contraction and Relaxation of Skeletal Muscle
14. What would happen to the ability to contract muscles if all ion gates were removed from the sarcolemma? The muscle wouldn't be able to contract because The ion channels allow for generation of electrical signals that lead to opening of the sarcoplasmic reticulum Ca++ receptors. 15. ____ Influence of blocking neural function on the ability to move the skeleton? If neural function is blocked then signals from the nervous system are not being sent to our muscles to move and without the muscles our skeleton does not move, so it would render the skeleton immobile
16. How could you tell if a motor unit functioned in strength or precision? The size of the motor unit defines its function. Small motor units that contain 2-20 muscle fibers per nerve fiber are found in muscles that function in precision. Large motor units that contain 100's-1000's of muscle fibers per nerve fiber are found in muscles that function in strength.
17. ____ Influence of blocking ACh receptors on the likelihood of muscle contraction.
Decrease. This is because ACh plays a crucial role in muscle excitation. Without ACh receptors, it cannot cross the synaptic cleft and bind in the sarcolemma of muscle fibers. Na+ channels would not be able to open and no excitation charge could be produced in the cell, thus, no muscular contraction could occur.
18. ____ Influence of removing muscle ACh receptors on the activity of neural voltage-gated calcium channels. NC If you removed the ACh receptors on the muscle cell would have no effect on the voltage-gated channels on the neuron 19. ____ Influence of removing T-tubules from the sarcolemma on the ability of a muscle to contract. D Without the t-tubules extending the plasma membrane deep into the cell you would only have Ca++ release at the superficial level of the cell, disallowing a synchronized muscle contraction. This would result in a weak muscle contraction.
20. What would happen if the sarcoplasmic reticulum was removed from a muscle fiber? if you did not have a way to sequester Ca++ you would not be able to regulate contraction by releasing it, causing either, tetany if you could not rid of the Ca++, or flaccid paralysis if you did not have any around.
21. ____ Influence of selectively destroying all troponin calcium receptors on the likelihood of muscle contraction. Calcium that flows out of SR and into cytoplasm/ around myofibrils bind to troponin, troponin changes shape, which moves tropomyosin, that exposes myosin head binding sites on actin, now the sites can bind to myosin. Myosin and Actin have to bind for a muscle contraction to occur.
22. What would happen if tropomyosin was non-functional? It would prevented it from moving OFF of the myosin binding sites then muscle contraction could not happen. If it was non-functional in a way that prevented ti from moving ON to the myosin binding site then the muscle contraction would not stop!
23. What would happen if tropomyosin could not bind calcium? this person would probably be completely unable to contract any skeletal muscles because the troponin-
tropomyosin complex would always block myosin from binding to actin; calcium ions would be unable to move the troponin-tropomyosin complex out of the way. 24. What is the physiologic significance of myosin heads binding ATP? Myosin heads binding ATP allows the myosin to "walk" down the actin protein. ATP that is bound to myosin heads hydrolyzes into ADP which releases energy. That energy is used to reorient the myosin head to a position that allows it to bind actin again, moving the M line toward the Z line. ATP also allows the myosin heads to detach from actin, extend again, wait for a myosin head binding site to open and then bind again, continuing to "walk" down the actin protein.
25. How could you tell if an individual could produce acetylcholinesterase? acetylcholinesterase is an enzyme that breaks down ACh in the synaptic cleft so that a contraction can stop. If we did have Acetylcholinesterase we could breakdown ACh allowing our muscles to relax. You can tell if someone was able to produce acetylcholinesterase based on the individuals ability to contract their muscles.
26. What would happen if a muscle had an overly stretched resting state? there would not be enough overlap between thick and thin filaments to produce an adequate cross bridge formation. The contraction produced by the muscle would be very weak and would have no tension in the muscle fibers. Behavior of Whole Muscles
27. What is the physiologic significance of the latent period of a muscle twitch?
a short delay (1-2 msec) from the time when the action potential reaches the muscle until tension can be observed in the muscle
.
28. ____ Influence of increasing muscle twitch stimulation frequency on the tension within the twitch?
The tension generated per twitch stimulation would be the same. What would change is whether or not the cell had fully recovered from the previous twitch stimulation. If not, then the total tension in the muscle fiber would increase (wave summation), but the tension generated per stimuli would be the same.
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29. How could you tell if a muscle contraction was isometric?
If a muscle contraction was isometric there would be no joint movement, the muscle would stay the same length, and there would be muscle tension. Muscle Metabolism
30. ____ Influence of destroying a muscle’s creatine phosphate on ATP production.
D, In the process of regeneration of ATP, creatine phosphate transfers a high-energy phosphate to ADP. The products of this reaction are ATP and creatine.
31. How could you tell if an individual had recently utilized anaerobic cellular respiration? There would be a drop in the individuals PH level because anaerobic respiration does not use oxygen, and produces lactic acid as a byproduct, which lowers cellular pH and decreases muscle contraction. Causing muscle enzymes efficiency to decrease because they are no longer working at the optimal pH.
32. What is the physiologic significance of aerobic cellular respiration? Aerobic cellular respiration is the primary process by which cells produce ATP with
oxygen. This type of cellular respiration also plays a crucial role in certain processes, such as muscle contraction, nerve signal transmission, protein synthesis, and active transport. Because Aerobic can make much more ATP from a single glucose in the presence of O2 than it's anaerobic counterpart, it is considered much more efficient in comparison. 33. _____ Influence of glycogen consumption on fatigue. Decrease, Glycogen is broken down to release glucose into the bloodstream to be used as fuel for the cells providing ATP. It is the stored form of a simple sugar called glucose.Therefore the consumption of glycogen (Glucose) boosts the individuals ATP level and decreases levels of fatigue.
34. What is the physiologic significance of heavy breathing during oxygen debt? Heavy breathing allows for 11 extra liters of oxygen in order to replace oxygen reserves, replenish the creatine phosphate system, convert lactic acid to glucose, and serve the elevated metabolic rate. Types of Skeletal Muscle Fibers
35. How could you tell if you were observing a slow oxidative or fast glycolytic muscle fiber?
Strength and Disorders. Slow oxidative fibers are darker in appearance (dark meat) due to having more mitochondria, myglobin, and capillaries. The have adapted to more aerobic respiration and long-term endurance activity. Fast glycolytic fibers have few mitochondria, myoglobin (leading to a lighter appearance), and capillaries. They are rich in glycogen and enzymes for creatine phosphate system, therefore have adapted for short-term intense, explosive anaerobic activity.
36. What would happen to muscle cell size if an individual performed endurance training? The muscle size would increase due to the increased production of myofibrils, mitochondria, sarcoplasmic reticulum, and other organelles. 37. What would happen if an individual became less and less sensitive to Ach? The individual would see their muscles become weaker and weaker due to possibly lacking the needed amount of Ach. Without Ach the body cannot tell the muscles to contract, leading them to become weaker due to remodeling after an extended period of lack of use. This phenomenon is called myasthenia gravis, and this also leads to difficulty of breathing and droopy eyelids. Chapter 12 Nervous Tissue Study Guide
STUDY CONCEPTS
Be able to define the following Keywords: afferent, ganglia, enteric nervous system, somatic sensory division, sympathetic division; excitability, soma, dendrite, axon, axoplasm, kinesin, fast retrograde axonal transport, bipolar neuron, interneuron, neuroglia, microglia, Schwann cell, myelin, neurolemma, oligodendrocytes, node of
Ranvier, nerve; graded potential, action potential, electrical potential, electrical current, voltage gated channel, ligand gated channel, graded, decremental, summation, depolarization, repolarization, hyperpolarization, tetrodotoxin, absolute refractory period, relative refractory period, continuous conduction, saltatory conduction; electrical synapse, chemical synapse, axodendritic, axoaxonic, ionotropic receptor, metabotropic receptor, inhibitory GABA-nergic synapse, excitatory cholinergic synapse, inhibitory cholinergic synapse, presynaptic inhibition; neurotransmitter, catecholamines, nitric oxide; Alzheimer disease, multiple sclerosis, and Parkinson’s disease. Overview of the Nervous System
List the three basic steps of neural communication. The chemical process of interaction between neurons and between neurons and effector cells occur at the end of the axon, in a structure called synapse through three phases: 1.
Excitability; respond to stimuli 2.
Conductivity; produce traveling electrical signals 3.
Secretion; release chemical when electrical signal reaches the end of the never fiber these chemicals are called neurotransmitters (ACH) Compare and contrast the two anatomical subdivisions of the nervous system. 1.The central nervous system (CNS) organs incased by bone such as the spinal cord and brain are the control centers that decide conscious or unconscious to respond to stimuli. Integrative function. 2. peripheral nervous system (PNS) organs NOT encased by bone such as Nerves- bundle of neuron axons in the CT. Ganglia- run along the nerve swelling of the neuron cell bodies in a nerve. Enteric plexus- neurons of GI tract doesn’t
need spinal cord or brain for communication. Sensory receptors- Neurons that monitor internal and external environments –
sensory path ways and –
motor pathways. The central nervous system is made up of the brain and spinal cord. The peripheral nervous system is made up of nerves that branch off from the spinal cord and extend to all parts of the body. Both systems composed of neurons and neuroglia
. List and describe the functional divisions and subdivisions of the PNS. peripheral nervous system (PNS) organs NOT encased by bone such as Nerves- bundle of neuron axons in the CT. Ganglia- run along the nerve swelling of the neuron cell bodies in a nerve. Enteric plexus- neurons of GI tract doesn’t need spinal cord or brain f
or communication. Sensory receptors- Neurons that monitor internal and external environments –
sensory path ways and –
motor pathways. Histology of Nervous Tissue List and describe the three properties of neurons. Soma- (cell body) -stella (star) shaped , single central nucleus, cytoskeleton composed of neurofibrils (actin), nerve fibers branch off processes dendrites( receive info) Axon(sends info), lipofuscin (the landfill) mass of worn out organelles hard to move with age implicated in macular degeneration Dendrites -information receiving processes of the neuron, receptor proteins for binding to external chemical messages, shorter and more numerous than the axon.
Axon -single, start at axon hillock (cone shaped elevation of the stoma), contains axoplasm (cytoplasm) and axolemma (plasma membrane), branches= axon collaterals, End at the synaptic end buld which contains synaptic vesicles neurotransmitters are stored in the vesicles.
Draw a typical neuron. Label the key components. Compare and contrast the three types of axonal transport. Slow axonal transport Anterograde. Down axon, away from soma. Fast anterograde axonal transport down the axon, away from the soma. Small molecules: organelles, enzymes, vesicles, neurotransmitters Fast retrograde axonal transport up axon, towards soma. for recycled materials and pathogens They all involve transport of molecules between soma and
axon/synaptic end bulb Compare and contrast the three fundamental types of neurons based on structure. Depending on the number of processes off a soma ~Multipolar neuron has MANY processes off soma, many dendrites/one axons, most common; motor neurons, integrative neurons ~Bipolar neuron has two processes from the soma, one dendrite and one axon, sensory: olfactory, retina and ear. ~Unipolar neurons; has only 1 process from the stoma, fused dendrites and axon, sensory receptors of the general senses(touch) What they all have in common: they all Receive signals (or information). Integrate incoming signals (to determine whether or not the information should be passed along)
. Compare and contrast the three fundamental types of neurons based on function. 1.
Afferent neurons- they transmit sensory and detect changes in the body, transmit information through the CNS and are mostly unipolar 2.
Interneurons/association neurons lie between sensory and motor pathways located in the CNS functions: information pathway (spinal cord) integration; process, store, retrieve information (make decisions) mostly multipolar. 3.
Efferent neurons they transmit motor information from the CNS out to the PNS and effectors and are mostly multipolar.
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The main types of neurons include motor neurons, which transmit information to our muscles, sensory neurons, which transmit information to enable our senses, and interneurons, which aid transmission between motor and sensory neurons. They all play a part in send and receive chemical and electrical signals.
List and describe the 4 neuroglia cells of the CNS and the 2 neuroglia cells of the PNS. 1.
Oligodendrocytes; form CNS myelin sheaths 2.
Ependymal cells; Line CNS cavities to produce and propel CSF 3.
MIcrogila; macrophages (originated in red bone marrow) that phagocytize dead tissue, foreign matter and microorganisms in CNS 4.
Astrocytes; most abundant neuroglia cell, structural framework of CNS contribute to blood brain barrier, convert glucose to lactate to feed neurons, secrete nerve growth factor, electrical influence on synaptic signaling. Describe myelin, and the two ways that myelin sheaths are formed. Which occurs where? Lipid and protein cover of axon, wrappings of plasma membrane lipid bilayers, speed up of signals traveling within the neuron the CNS (oligodendrocyte) myelinate several fibers at once, no neurolemma, nodes of Ranvier are still present and the PNS (Schwann) Schwann cell spirals around axon creating hundreds of layers of plasma membrane, the outermost coil is Schwann cell body (neurolemma) Nodes of Ranvier are the empty spaces between Schwann cells. List and describe the 4 different types of neural tissue found in the CNS and PNS PNS -Ganglion; a cluster of neural cell bodies/ somas -Nerve; a bundle of neural axons CNS
-White matter (tracts); bundles of myelinated neural axons -Gray matter; bundles of neural cell bodies, dendrites and axon terminals An individual neuron does not exist in only one type of tissue because of axons and somas Electrophysiology of Neurons
Compare and contrast graded and action potentials. Graded potentials occur in dendrites when a neuron is stimulated by chemicals, light, heat, or mechanical disturbance. They vary in size with stimulus strength. They build on previous potential with rapid stimuli decremental; they get weaker the farther they spread because of diffusion the similarities between graded and action potentials is that they can both be excitatory however individual action potentials are larger graded cause of increased frequency not larger signals and they do not get weaker with distance.
Be able to describe in general the formation of potentials during a simple sensory to motor action. 1.Touching the pen initiates a graded potential in a sensory receptor 2.The GP initiates an action potential in the axon of the sensory neuron •
The AP travels along the axon & causes the sensory neuron to release neurotransmitters at an interneuron in the CNS stimulus 3.The neurotransmitters initiate a graded potential in the interneuron 4.The GP in the interneuron initiates an action potential •
The AP travels along the axon and causes the interneuron to do what? neurotransmitters •
Steps 3-4 repeat until the message reaches the brain 5.A decision to use the pen is made by brain 6.After the decision a graded potential is generated in an upper motor neuron •
The GP initiates an action potential in the axon of the upper motor neuron •
The AP travels along the axon & causes the motor neuron to release neurotransmitters at a lower motor neuron in brain 7.The neurotransmitters initiate a graded potential in the lower motor neuron •
The GP initiates an action potential in the axon of the lower motor neuron •
The AP travels along the axon & causes the motor neuron to release neurotransmitters at the NMJ
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•
Which neurotransmitter is released? ACH_ 8.The muscles will contract. Compare and contrast the 4 most common types of ion channels. Leak channels Open randomly; graded potentials Ligand-gated channels Open when bound to a chemical stimulus (ligand); graded potentials Mechanically gated channels Open in response to vibration, touch, pressure, or stretch; graded potentials Voltage-gated channels Open in response to changing membrane potential; action potentials What they all have in common: all channels open as a response to stimulus. List and describe the three components that contribute to generation of the resting membrane potential. Resting membrane potential is due to unequal electrolyte distribution in and out of the cell 3 main contributors to -70 charge 1.K
+ ions diffuse down concentration gradient out of the cell through leak channels What does this do to the charge in the cell? make it more negative 2.Cytoplasmic anions (- charge) cannot escape due to size (organic acids, proteins) What does this do to the charge in the cell? make it more negstive 3.Na
+
/K
+
pump Continuously pumps out 3 Na
+
for every 2 K
+
it brings in Works continuously and requires great deal of ATP What does this do to the charge in the cell? makes it more negative K+ is always higher inside of the cell Describe a graded potential. Graded potentials occur in dendrites when a neuron is stimulated by chemicals, light, heat, or mechanical disturbance. In general…
Stimulus causes ion channels to open Ions enter or leave the cell leading to a charge change within the cell Hy
perpolarize: inside becomes more negative Prevents AP Depolarize: inside becomes less negative more likely to generate AP Describe the 5 phases/steps of an action potential. •
Resting membrane potential
: Voltage gated Na
+
& K
+
channels are closed •
Stimulus
: Change in voltage from upstream graded potentials increase voltage at trigger zone •
Depolarization
: if the stimulus reaches threshold the voltage gated Na
+
channels in the trigger zone open
•
What happens Na+ floods the cell •
Repolarization
: After 0mV, voltage gated Na
+
channels close and voltage gated K
+
channels open •
What happens k+ leaves the cell and becomes negative •
After-Hyperpolarizing phase/hyperpolarization
: Voltage gated K
+
channels close slowly and more K
+
is lost than is needed to reach the resting membrane potential •
What happens hyperpolarized (more negative)
What are three characteristics of a graded potential that differ from an action potential? Graded potentials •
Graded: Vary in size with stimulus strength •
Summation: Build on previous potential with rapid stimuli •
Decremental: Get weaker the farther they spread because of diffusion •
Can be either excitatory or inhibitory •
Inhibitory hyperpolarize cell making the membrane more negative!
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Individual Action potentials •
All-or-none: Larger graded cause increased frequency, not larger signals •
Do not get weaker with distance •
Always excitatory Compare and contrast relative and absolute refractory periods. Refractory period Period of resistance to stimulation 2 different types: 1.Absolute refractory period •
During ongoing depolarization & repolarization •
No stimulus will trigger AP •
Limits to 10-1000 signals/s depending on size of neuron 2.Relative refractory period •
During hyperpolarization •
Especially strong stimuli can trigger new AP •
Prevents sequential action potentials from traveling up the axon to the soma Describe the mechanism of impulse conduction down both unmyelinated (continuous) and myelinated (saltatory) axons. Unmyelinated fibers •
Have voltage gated Na
+
channels entire length •
The nerve signal is a chain reaction of sequential action potentials •
Sequential opening of voltage-gated Na
+ channels down the length of an axon •
Why don’t the signals go backwards? because relative refractory period upstream of action potential •
Speed = 1-4 mph •
Dominoes are stacked together Myelinated fibers •
Voltage-gated channels are located only at the Nodes of Ranvier. •
Why? only points where membrane is next to (ECF) extracellular fluid •
Na+ cannot enter the axon in regions where it is myelinated. •
If an axon was entirely myelinated, could APs be generated? no •
APs only occur at nodes of Ranvier •
Fast Na+ diffusion occurs in axoplasm between nodes which opens voltage gates in the next node, creating a new action potential •
27-290 mph •
There is no loss of Na+ along the axon within myelinated regions •
More energy efficient: •
Do not need to drive as many Na+/K+ pumps.
Compare and contrast saltatory and continuous conduction. Saltatory conduction is faster than continuous conduction, Continuous conduction of action potentials occurs in non-myelinated axons, while saltatory conduction occurs in myelinated axons.
In both paths, the action potential is produced, and both of the pathways involve the use of ion channels.
Electrical and chemical synapses exist within the same networks of inhibitory cells, Synapses
Compare and contrast electrical and chemical synapses.
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At chemical synapses, the information is transferred via the release of a neurotransmitter from one cell that is detected by an adjacent cell, whereas in the in the case of electrical synapses the cytoplasm of adjacent cells are directly connected by clusters of intercellular channels called gap junctions. Compare and contrast axodendritic, axosomatic, and axoaxonic synapses. Axosomatic synapses are synapses that are made onto the soma or cell body of a neuron. Axodendritic synapses, probably the most prominent kind of synapses, are synapses that one neuron makes onto the dendrite of another neuron. Axoaxonic synapses are synapses made by one neuron onto the synapse of another neuron.they all work together to stimulate another cell.
Describe the general mechanism of a synapse. A synapse is a junction through which a neuron passes information to another neuron. Presynaptic terminals contain chemical neurotransmitters enclosed in small spherical intramembrane structures called synaptic vesicles Compare and contrast ionotropic and metabotropic receptors. ionotropic: contain channels, receptor because it binds neurotransmitter
metabotropic: does not have a channel, place for neurotransmitter to bind and inside there is a g-protein. Ionotropic and metabotropic receptors are both ligand-gated transmembrane proteins
. Describe in detail the steps of the three example mechanisms of synaptic transmission (excitatory cholinergic, inhibitory cholinergic and inhibitory GABA-nergic). Excitatory cholinergic synapse -a synapse that employs acetylcholine (ACh) as its neurotransmitter -"regular synapse" Step 1 (Excitatory cholinergic synapse) The arrival of a nerve signal at the synaptic knob opens voltage-gated calcium channels. Step 2 (Excitatory cholinergic synapse) Ca2+ enters the knob and triggers exocytosis of the synaptic vesicles, releasing ACh. Step 3 (Excitatory cholinergic synapse) Empty vesicles drop back into the cytoplasm to be refilled with ACh, while synaptic vesicles in the reserve pool move to the active sites and release their ACh
—
a bit like a line of Revolutionary War soldiers firing their muskets and falling back to reload as another line moves to the fore. Step 4 (Excitatory cholinergic synapse) Meanwhile, ACh diffuses across the synaptic cleft and binds to ligand-gated channels on the postsynaptic neuron. These channels open, allowing Na+ to enter the cell and K+ to leave. Na+ and K+ pass in opposite directions through the same gates. Step 5 (Excitatory cholinergic synapse) As Na+ enters, it spreads out along the inside of the plasma membrane and depolarizes it, producing a local voltage shift called the postsynaptic potential. Like other local potentials, if this is strong and persistent enough (that is, if enough current makes it to the axon hillock), it opens voltage-gated ion channels in the trigger zone and causes the postsynaptic neuron to fire. Inhibitory GABA-ergic synapse -GABA-nergic synapse employs -aminobutyric acid as its neurotransmitter -Nerve signal triggers release of GABA into synaptic cleft -GABA receptors are chloride channels -
Cl− enters cell and makes the inside more negative than the resting membrane potential
-Postsynaptic neuron is inhibited, and less likely to fire Inhibitory GABA-ergic synapse
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-GABA-nergic synapse employs -aminobutyric acid as its neurotransmitter -Nerve signal triggers release of GABA into synaptic cleft -GABA receptors are chloride channels -
Cl− enters cell and makes the inside more negative than the resting membrane potential
-Postsynaptic neuron is inhibited, and less likely to fire Know how neural signals end. Action potentials travel down a single neuron cell as an electrochemical cascade, allowing a net inward flow of positively charged ions into the axon. Within a cell, action potentials are triggered at the cell body, travel down the axon, and end at the axon terminal
.
Neurotransmitters
List the 5 general characteristics of neurotransmitters. -small organic molecules that contain carbon.
-synthesized by pre-synaptic neurons
-released in response to stimulation (AP)
-bind specific receptors on post-synaptic cell
-alter physiology of post-synaptic cell List and describe four types of small neurotransmitters. > Acetylcholine (ACh) Excitatory or inhibitory > Amino acids Glutamate (inhibitory in detina) Mosty excitatory neurons in CNS GABA inhibitory, anti-anxiety drugs (valium) enhance GABA action > Catecholamines Regulate brain activity involved in mood, lack can lead to depression disorders Norepinephrine, epinephrine, dopamine (lack leads to Parkinson disease) serotonin. >Nitric Oxide Regulates blood vessel wall permeability, erection, viagra inhibits nitric oxide inhibitors increasing erection Neural Disorders
Describe the limitations of neural tissue growth. -Plastic but not proliferative meaning can change but not grow back - the capability to change based on experience, existing neurons are rearranged creating, eliminating, or modifying synapses. - Regeneration is limited, can repair damaged axons and somas in the PNS but not the CNS, oligodendrocytes rather than Schwann cells.
Compare and contrast multiple sclerosis, Alzheimer’s disease and Parkinson’s disease. AD
: degeneration of cholinergic neurons and deficiency of ACh and nerve growth factors. -100,000 deaths per year 11% od population over 65; 47% by age 85 - memory loss for recent events, moody, combative, lose ability to talk, walk and eat. - the underlying cause is presumed to be degeneration of cholinergic neurons and deficiency of ACh and nerve growth factors. - genetic connection is confirmed. MS
: degeneration of oligodendrocytes and myelin sheaths in CNS replaced with scar tissue (fibrosis) -weakness in muscles, abnormal sensations and double vision. -Two people worldwide -Appears between the ages of 20 and 40 -Autoimmune disease females are more likely to have this due to looseness in the immune system. -genetic and viral contributions. PD
: progressive loss of motor function beginning in the 50’s and 60’s no recovery -underlying cause is a degeneration of dopamine releasing neurons ( dopamine prevents excessive activity in motor centers of the brain and involuntary muscle contractions. - treatment; drugs and PT SIMILARITY: all degenerative diseases
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STUDY QUESTIONS
Overview of the Nervous System
1.How could you tell if you were observing a component of the CNS or PNS? The CNS includes two organs, the brain and spinal cord. The PNS peripheral nervous system is everything else and includes nerves that travel from the spinal cord and brain to supply the face and the rest of your body. 2._____ Influence of blocking the central nervous system on the ability to respond to a particular stimulus. Decrease -- the central nervous system is responsible for integration. The integrative function of the nervous system is when the brain and spinal cord (central nervous system) determine responses to information received from sense organs. If the central nervous system was blocked, responses to stimuli would also be blocked. 3.What would happen if the somatic motor division did not function? The somatic MOTOR division is the set of neural pathways that communicate information to our skeletal muscles. So without the somatic motor division, we could not move our skeletal muscle. Histology of Nervous Tissue
4.How could you tell a neuron had the property of secretion? the neuron would release acetylcholine. This secretion would takes place after the neuron goes through the two prior properties, including excitability and conductivity 5.What is the physiologic significance of a dendrite? dendrites are the information receiving processes of the neuron and are receptor proteins for binding to external chemical messages. The dendrites are shorter and more numbers than the axon. 6._____Influence of blocking slow axonal transport on the ability of a neuron to move proteins towards the soma. Axonal transport consists of the process of moving molecules between the soma and the axon. So, blocking slow axonal transport should not affect the Retrograde axonal transport's ability to move proteins toward the soma. Since slow axonal transport works by moving down the axon and away from the soma. 7.How could you tell by looking at the synaptic knob
, if a neuron was able to conduct axonal transport? In the synaptic knob, you would need to see voltage gated Calcium channels, Acetylcholinesterase enzymes, and Acetylcholine neurotransmitters if a neuron able to conduct axonal transport. 8._____ Influence of removing motor neurons on the ability of an individual to sense external stimuli. N, Efferent motor neurons carry output signals to effectors. Afferent sensory neurons detect stimuli. 9.What would happen if ependymal cells were destroyed? Ependymal cells are a type of CNS neuroglia cell that line the CNS cavities to produce and propel cerebral spinal fluid. Without ependymal cells there would be no CSF, causing a build up of wastes, no nutrients delivered. 10._____ Influence of destroying Schwann cells on the level of myelination in the CNS. None, for CNS myelination oligodendrocytes are needed, while Schwann cells are needed for PNS myelination. 11.What is the physiologic significance of oligodendrocytes? Oligodendrocytes produce myelin which forms sheaths of myelin covering the axons. Myelin sheaths facilitate the transmission of electrical signals across axons more quickly and they’re significant because signals wouldn't move as quickly. these cells perform these functions in the CNS. 12.What is the physiologic significance of myelin? Myelin is a lipid and protein cover of an axon that increases the speed of signals traveling within the neuron Electrophysiology of Neurons 13.How could you tell if you were observing a region of plasma membrane that was experiencing a graded or an action potential? Graded potentials rely on mechanically-gated, ligand-gated, or leaky ion channels. Action potentials rely on voltage-gated ion channels. Action potentials always use positive ions. Graded channels can use negative ions. Action potentials occur on the axon. Graded potentials can occur anywhere on a neuron, but primarily the dendrites and soma.
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14.How could you tell if you were observing a voltage gated channel or a ligand gated channel? By what causes the channel to open/how. In a voltage gated channel, they open in response to changing membrane potentials, they are involved in creating action potentials. In Ligand gated channels they open when bound to a chemical stimulus(ligand) and are involved in creating graded potentials. 15.What is the physiologic significance of a resting membrane potential? A resting membrane potential is when a membrane is at rest but has the potential to produce a current. The inside of the membrane has a negative charge and when it becomes more positive this creates a current. This is helpful for the body because it allows us to produce currents when needed without having to constantly produce them. 16.What would happen if a local disturbance stimulated the opening of Na
+
gates in a region of the plasma membrane that had a negative resting membrane potential? Stimulus causes gated Na+ channels to open and Na+ will flow into the cell, increasing/depolarizing the charge in the cell. Na+ has the ability to diffuse for short distances inside the cell producing a change in voltage along the membrane which would be a graded potential. 17.What is the physiologic significance of graded potentials being graded and decremental? They are important so that we only generate action potentials in response to big enough graded potentials
....
thus stimuli that need addressing. Decremental refers to the decrease in charge that occurs in the cell as ions enter and diffuse away from the source. So, the more ion channels that are open, the more ions in the cell, the further the ions can diffuse and still create charges within the cell. 18._____ Influence of a graded potential reaching threshold level at the axon hillock on the likelihood of generation of an action potential. I, If a graded potential is large enough it will automatically generate an action potential. Dramatic changes in membrane potential lead to a communication down the axon, which will produce action potential in the "trigger zone on the axon hillock. Each action potential triggers a subsequent action potential further down the axon. 19.What would happen if Na
+
gates did not close after the membrane potential reached 0mV? Na+ channels are to close when 0mV is reached. This then allows voltage gated K+ channels to open. K+ then flows out of the neuron so the charge decreases. This overall restores resting membrane potential, which would not occur if the Na+ gates did not close after the membrane potential reached 0mV. 20.How could you tell if a membrane was in an absolute or relative refractory period? Absolute: during ongoing AP. No stimulus can trigger another AP at this time.
Relative: During hyperpolarization. Membrane is less than -70. A large stimulus could trigger another AP. 21.What is the physiologic significance of refractory periods? It is the period of time after an action potential begins during which an excitable cell cannot generate another action potential in response to a normal threshold stimulus. They are important so that generated electrical currents travel in the proper direction. 22.What would happen if nodes of Ranvier were covered with myelin? the voltage gated Na+ channels would also be covered. With these channels covered sodium wouldn't be able to continue depolarizing the axolemma and continue down to the distal end of the axon to the synapse. The original action potential would be lost. Synapses
23.How could you tell if a synapse was electrical or chemical? The electrical synapse is cell to cell connected by using gap junctions. The chemical synapse is secreted chemicals that are referred to as neurotransmitters, on of which is the neuromuscular junction. 24._____ Influence of blocking voltage gated Ca No change. ACh is produced in the soma and transported via axonal transport to the synaptic knob. An influx of Ca2+ would cause exoctosis of ACh, not production of ACh. 2+
channels on the synaptic knob on the ability of the neuron to produce ACh. . By looking at the neurotransmitters and ion channels involved.
EPSPs result from excitatory
neurotransmitters, causing an increase of Na+ ions and depolarizing the membrane
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potential.
IPSPs stem from inhibitory neurotransmitters, leading to an increase of - ions or an efflux of + ions, hyperpolarizing the membrane potential and making it less likely for the neuron to fire an action potential. 26.How could you tell if a post-synaptic potential was an EPSP or an IPSP? By looking at the neurotransmitters and ion channels involved.
EPSPs result from excitatory
neurotransmitters, causing an increase of Na+ ions and depolarizing the membrane potential.
IPSPs stem from inhibitory neurotransmitters, leading to an increase of - ions or an efflux of + ions, hyperpolarizing the membrane potential and making it less likely for the neuron to fire an action potential. 27.What is the physiologic significance of GABA triggering Cl
-
gates in a post-synaptic neuron? GABA from presynaptic neuron opens Cl- channel on the postsynaptic neuron. Cl- flows into the channel and the charge in the cell decreases. This leads to hyperpolarization which decreases the chances that the postsynaptic cell will have an action potential. 28.What is the physiologic significance of pre-synaptic inhibition? Presynaptic inhibition is the reduction of transmitter released from an excitatory presynaptic terminal by axoaxonic inhibitory synapse. This process plays a crucial role in normal function of the contraction cycle in a muscle, without presynaptic inhibition one would lose ability to contract their muscles causing paralysis. 29.What would happen if EPSPs underwent summation to a threshold level in the trigger zone? Neurotransmitters are important for producing responses to stimulation. They are chemicals secreted by a neuron that travels acroos an extracellular gap and binds to receptors on a second cell. They are synthesized by pre-
synaptic neurons, released in response to a stimulation or an action potential and change the physiology of a post-
synaptic cell. Neurotransmitters
30.What is the physiologic significance of neurotransmitters? They are e
ndogenous chemicals that allow neurons to communicate with each other throughout the body
. Neural Disorders
31.
____ Influence of degeneration of cholinergic neurons on the progression of an individual’s Parkinson’s disease. I, cholinergic neurons release ACh, a neurotransmitter that allows impulses to be fired at the synaptic cleft. However, during aging, the release of this neurotransmitter is decreased. 32.
What would happen if an individual’s CNS myelin sheaths degenerated and were replaced with scar tissue? Scar tissue is Fibrosis healing from degeneration of oligodendrocytes and myelin sheaths in the CNS which causes multiple sclerosis ____ 1. Influence of removing synovial fluid from a cartilaginous joint on the probability of proper joint function. N, synovial fluid provides lubrication for synovial joints. Cartilaginous joints only contain cartilage. N, synovial fluid feeds the cartilage in a synovial joint. Cartilaginous joints only contain cartilage. ____ 2. Influence of being double jointed on an individual’s range of motion (ROM). N, no such thing; decreased tautness of joint capsule, ligaments and tendons increases ROM. N, no such thing; ROM is determined by nervous system and muscle activity and shape of articular surface ____ 3. Influence of osteoarthritis on the development of bone spurs. I, years of wear and tear on the joint degrade articular cartilage leading to increased stress, remodeling ____ 4. Influence blocking neural function on the ability to move the skeleton. D, to contract, skeletal muscle must be directed to do so by somatic motor neurons. ____ 5. Influence of destroying all troponin Ca
++
receptors on the ability of a muscle to contract. D, Ca
++
binds to troponin, troponin changes shape moving tropomyosin exposing myosin head binding sites ____ 6. Influence of glycogen consumption on fatigue. I, as cells utilize glycogen, they decrease the amount of glucose thus ATP they can produce. D, if you eat glycogen, it will get stored in your muscles leading to more glucose thus ATP availability ____ 7. Influence of removing motor neurons on the ability of an individual to sense external stimuli.
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N, Efferent motor neurons carry output signals to effectors. Afferent sensory neurons detect stimuli. ____ 8. Influence of destroying tendon sheathes on the ability to efficiently move your fingers. D, tendon sheaths are elongated bursae filled with synovial fluid that wrap around tendons and cushion and ease movement between tendons, muscles, bone and skin. ____ 9. Influence of changing a hinge joint to a pivot joint on the number of planes the distal bone moves through. N, both joints are uniaxial and move the distal bone through only one plane.
____ 10. Influence of destroying muscle fibers extensibility characteristic on its long-term function. D, extensibility is the ability to the muscle fiber to stretch without being damaged. ____ 11. Influence of increasing the number of somatic motor neurons innervating a muscle on the ability of the muscle to create precise movements. I, the more somatic motor neurons a muscle fiber the greater number of smaller motor units it will have. ____ 12. Influence of overstretching a muscle fiber prior to contraction on the amount of tension that can be developed during contraction. D, if overstretched/under-contracted, there is a little thin and thick filament overlap not enough cross bridges can form and a weak contraction occurs.
____ 13. Influence of blocking slow axonal transport on the ability of a neuron to move proteins towards the soma. N, slow axonal transport moves large compounds down the axon to the synaptic knob. Fast retrograde transport moves proteins towards the soma.
____ 14. Influence of destroying Schwann cells on the production of cerebrospinal fluid. N Schwann cells myelinate the PNS. Ependymal cells produce CSF. II. Each image below illustrates an anatomic or physiologic principle. Above each image is stated a condition, which might cause the situation illustrated in the image to change
. Draw the appropriate modification (change) directly on the image
to illustrate the “new” response. Give a brief justification for why the change took place
. HINT: It may be easier to describe the written principle first and change the image second. (8 points –
2 points for graph, 2 points for justification) A. This osteoclast was exposed to parathyroid hormone. B. An electrical signal reached the end of the neuron at this neuromuscular junction. (Note: junctional folds have been removed from the sarcolemma for simplification)
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III. Fill in the blank. (14 points: 1 point per blank) 1. Fill in the blanks regarding bone physiology. Calcitonin is a hormone that corrects hypercalcemia in children. Cholecalciferol is a precursor of vitamin D that is produced by the skin from cholesterol in response to UV light exposure. 2. Fill in the blanks regarding joints. A condyloid joint occurs where an oval convex surface on one bone articulates with a depression on another bone. A hinge joint, such as the elbow, only allows movement of the distal bone through one anatomical plane. Synovial joints classified as ball and socket joints are the only joints that are exclusively triaxial. 3. Fill in the blanks regarding skeletal muscle. Skeletal muscle fibers have striations. The H-zone is in the very middle of the A band and serves as space for the thin filament to migrate into. The I-band is bisected by the Z-disc. The technical name for a point where a neuron meets its target cell is the synapse . The end of the neuron that interacts directly with the target cell is called the synaptic knob . 4. Fill in the blanks regarding behavior of whole muscles. The twitch is the smallest, imperceptible contraction of all the muscle fibers in a motor unit in response to a single action potential in its motor neuron. Wave summation occurs when a muscle fiber is stimulated prior to completing the relaxation stage, resulting in a larger second contraction. isometric muscle contraction is when contraction develops tension without changing length. 5. Fill in the blanks regarding the nervous system. The neurolemma is the outer most portion of the Schwann cell that we can see. The spaces between individual Schwann cells are the nodes of renvier
. IV. Discussion. (14 points)
A. Compare and contrast calcitonin and parathyroid hormone. (1 point) Both hormones that regulate blood calcium; calcitonin from thyroid gland, PTH from parathyroid gland PTH increases blood calcium; Calcitonin decreases blood calcium; both hormones regulate blood calcium PTH stimulates osteoclasts; Calcitonin stimulates osteoblasts; both hormones regulate blood calcium B. Which of the following is/are characteristics of rheumatoid arthritis
: more common in females, wear and tear on joints, caused by osteoporosis, only effect sutures, cancer
? (1 point) C. Which of the following is the correct sequence of events? (1 point) ATP hydrolysis, cross-bridge formation, power stroke, myosin detachment
D. Which of the following is/are glia cells of the PNS? Schwann cells
, microglia, Langerhans cells, astrocytes, oligodendrocytes, fibroblasts, ependymal cells, melanocytes. (1 point) E. Describe the process of fracture repair. (3 points) 1, hematoma formation; fracture breaks blood vessels and a clot form. 2, fibrocartilage callus formation; fibroblasts from periosteum deposit collagen and chondrocytes from periosteum produce fibrocartilage. 3 bony callus formation; osteoblast produce tuberculate and spongy bone 4; bone remodeling; spong bone is replaced by compact bone. F. Compare and contrast the different types of muscle tissue. (2 points) All shorten to provide movement. Skeletal: striated, multinucleated, attached to bone, voluntary. Cardiac; striated, 1 nucleus, in heart. Smooth; not striated, 1 nucleus, internal organs. G. Describe 4 events that must occur for muscle relaxation to occur. (2 points) Detachment of myosin from myosin head binding sites on actin; Detachment of calcium from troponin; Active transport of calcium back into terminal cisternae; return of tropomyosin over myosin head binding sites , degradation of ACH by acetylcholinesterase; muscle fiber returns to resting length b/c of elastic recoil. H. Draw a typical neuron. Label key components. (2 points)
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I. Describe myelin. Wrappings of plasma membrane lipid bilayers that↑ the speed of signals traveling in the neuron
V. What is the physiologic significance of...? Briefly explain why each is important. Do not give a definition, but tell what the significant contribution(s) each makes. (12 points: 2 points each) 1. increased age on a female’s bone function? Lack of estrogen causing decreased bone density and increased brittleness leading to osteoporosis Life-long remodeling of bone to maximize stress resistance for a given female, decreased fracture chances 2. myostatin? Embryonic protein that causes myoblast stem cell to stop proliferating and begin fusing 3. heavy breathing during oxygen debt? Replace oxygen reserves in myoglobin, blood hemoglobin, air in the lungs & dissolved in plasma Replenish the creatinine phosphate system Convert lactic acid to glucose in kidneys and liver Serve the elevated metabolic rate that occurs as long as the body temperature remains elevated by exercise 4. articulation? Any point where 2 bones come together to provide movement or protection of soft organs. 5. the perimysium? Dense irregular CT that surrounds bundles of muscle cells called fascicle contains nerves and vasculature inside of epimysium around the endomysium. 6. aerobic cellular respiration? Production of ATP from glucose with oxygen. Provides for minutes to hours of maximum activity. VI. What would happen …? Describe what would happen in each scenario below. (12 points: 2 points each) A. if a diarthrosis became a synarthrosis? Would change from being freely movable to non-movable B. if all sarcoplasmic reticulum was removed from a muscle fiber?
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No terminal cisternae to store calcium, inability to contract muscle C. if an individual developed a hereditary disease of a mutated dystrophin? Muscular dystrophy; skeletal muscles degenerate, replaced with adipose and scar tissue D. if a fetus developed fully formed sutures before birth? No fontanels to allow cranial bone shifting to ease birth and facilitate brain growth. E. if all dystrophin was removed from an individual’s muscle fibers? Sarcolemma would not be anchored to sarcomere, muscular dystrophy would occur myofibril would contract in cell. F. if the somatic motor division did not function? No signals from the CNS would travel to the PNS to regulate skeletal muscle contraction. VII. How could you tell …? Please give a concise answer to each. (12 points: 2 points each) 1. the difference between a symphysis and a synchondrosis? Both cartilaginous joints; Synchondroses = hyaline cartilage; symphysis = fibrocartilage 2. if you were observing a thin filament or a thick filament? Thick: contains myosin protein; thin: contains troponin, tropomyosin and actin 3. if you were observing a slow oxidative (SO) or fast glycolytic (FG) muscle fiber? SO: slow contraction; FG: fast contraction SO: more mitochondria and capillaries; FG: more glycogen and creatinine kinase SO: resistant to fatigue; FG: fewer mitochondria 4. the difference between a suture and a syndesmosis
?
Both=fibrous joints. Suture between cranial bones. Syndesmosis between tooth and alveolus. 5. if a muscle fiber was maximally contracted, by only looking at its striations? Minimal/absent Hzone and Iband. Thin and thick filaments overlap the Aband 6. if you were observing a component of the CNS or PNS? CNS encased in bone:brain and spinal cord.PNS:not encased in bones=nerves and ganglia VIII. Bonus: (2 points) A. How many neural signals/second lead to fused tetanus? 100 B. How long after death does it take for rigor mortis to begin? 4 hrs C. What percentage of your body weight is your nervous system? 3% D. Argue why one of the articulations discussed could be considered not to be an articulation. Bones, articulation is when two bones come together bony joints are just bone connected to bone all the way through , nothing is between Compare and contrast calcitonin & parathyroid hormone, including; where they are produced, how they affect blood calcium levels, and the mechanisms they use to change blood calcium levels. Calcitonin- - Antagonizes PTH - Decreases blood calcium - Stimulates osteoblasts - Inhibits Osteoclasts Parathyroid hormone- - They produce PTH - Raises blood calcium level. - Stimulates osteoclasts - Inhibits Osteoblasts Similar -
Both help regulate the level of calcium in your blood
,
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Compare and contrast the three classifications of joints based on degree of movement. Synarthroses- - Immovable joints Ex: Adult suture amphiarthroses- - Slightly movable Ex: Pubic symphysis diarthroses- - Freely movable joints Ex: Shoulder, knee, elbow Similar- -all allow movement Compare and contrast interosseous membranes and syndesmoses.
Syndesmoses- - Greater distance between articulating surfaces with more dense collagen than in a suture. - Slightly movable Ex: Anterior tibiofibular ligament, Gomphoses (dentoalveolar joint) Interosseous membranes- - Where two bones are bound by a substantial sheet of dense irregular connective tissue - Slightly movable Ex: Interosseous membrane unite radius to ulna and Tibia to the fibula. Similar- -both found in a fibrous joint Compare and contrast the two types of cartilaginous joints.
synchondroses- - Very little movement - they are joined by hyaline cartilage. Symphyses- - Bones joined by fibrocartilage - Amphirathrosis Similar- Compare and contrast saddle and pivot joints. Pivot- - Saddle shaped surfaces of two bones articulate with each other - Biaxial Saddle- - First bone rotates on its longitudinal axis relative to other - uniaxial Similar- - Both of them are types of synovial joints. Compare and contrast hinge, condyloid, and ball-and-socket joints Hinge- A linear convex surface on one bone articulates with a concave depression on another bone. Ex: Elbow, knee. - Uniaxial Condyloid - An oval convex surface on one bone articulates with depression on another bone. Ex: Radiocarpal and metacarpophalangeal
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- Biaxial. Ball-and-socket- A smooth hemispherical head on one bone articulates with a cuplike depression on another bone Ex: hip and shoulder joint - Triaxial Similar- all contribute to range of motion Compare and contrast sarcoplasmic reticulum and T-tubules. Sarcoplasmic reticulum- Smooth ER Forms a network each myofibril T-tubules- Tunnel-like in-foldings of sarcolemma Similar- Compare and contrast thin and thick filame
nts. Thin filaments are comprised mostly of the protein actin•
Thick filaments are comprised mostly of the protein myosin Similar- Contraction occurs in sarcomere because of interaction b/t thin and thick filaments Compare and contrast regulatory and contractile proteins
Contractile proteins Proteins that interact to shorten the sarcomere to generate force during a contraction - Myosin; actin Regulatory proteins Proteins that regulate the contractile proteins - troponin; tropomyosin Similar The switch that starts and stops shortening of muscle cell (maybe) Compare and contrast large and small motor units.
Large-
Large motor units (100’s
- 1000’s of muscle fibers per nerve fiber) are found in muscles that function for strength control (gastrocnemius) small- Small motor units (2-20 muscle fibers per nerve fiber) are found in muscles that function for precision (eye muscles) similar- Compare and contrast junctional folds and synaptic end knobs.
Junctional folds- Folds in sarcolemma that increase surface area for ACh receptors Synaptic end knobs- • End of neuron fiber
• Contains vesicles filled with a chemical neurotransmitter
Similar- Compare and contrast cross bridges and the power strokes.
Cross-Bridge Formation - The reoriented myosin head can now bind to exposed myosin head binding sites on actin forming a cross-bridge - Half of the myosin heads on a thick filament are bound to a thin filament at one time Power stroke ADP is released causing the myosin head to return to original position towards the M-line Similar- Compare and contrast isometric and isotonic muscle contractions. Isotonic muscle contraction- When muscle length changes while contracting
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- tension while shortening = Isotonic concentric contraction - Tension while lengthening = Isotonic eccentric contraction Isometric muscle contraction- Contraction develops tension without changing length. - Important in postural muscle function and joint stabilization similar- Compare and contrast the creatine phosphate system, anaerobic cellular respiration, and aerobic cellular respiration.
creatine phosphate- An energy storage molecule used by muscle tissue. The phosphate from creatine phosphate can be removed and attached to an ADP to generate ATP quickly. anaerobic cellular respiration- Production of ATP from glucose w/out Oxygen aerobic cellular respiration- Production of ATP from glucose with oxygen Similar- Compare and contrast endurance and fatigue.
Endurance- The ability to maintain high-intensity exercise for >5 minutes Fatigue- Inability of a muscle to maintain force of contraction after prolonged activity Similar- Compare and contrast resistance and endurance training.
Resistance training- Stimulates cell enlargement due to synthesis of myofilaments Endurance training- Produces an increase in mitochondria, glycogen & density of capillaries Similar- Compare and contrast muscular dystrophy and myasthenia gravis.
Muscular Dystrophy- Hereditary disease of a mutated dystrophin - Skeletal muscles degenerate and are replaced with adipose and scar tissue Myasthenia Gravis- Autoimmune disease in which antibodies attack NMJ and bind/block ACh receptors - As ACh receptors are lost, muscles become increasingly weaker, fatigue easily, & may cease to function similar- Compare and contrast the two anatomical subdivisions of the nervous system.
Central nervous system (CNS)- - Organs encased by bone 1. Brain 2. Spinal cord - Integrative function Similar- Peripheral nervous system (PNS)- - Organs not encased by bone 1. Nerves 2. Ganglia 3. Enteric plexuses 4. Sensory receptors
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Compare and contrast the three types of axonal transport.
Slow axonal transport 1. Anterograde - Down axon, away from soma Fast axonal transport 2. Fast anterograde axonal transport - Down axon, away from soma 3. Fast retrograde axonal transport - Up axon, towards soma. Compare and contrast the three fundamental types of neurons based on structure.
Multipolar neuron - Many dendrites/one axon - Most common; motor neurons, integrative neurons Bipolar neuron - One dendrite/one axon - Sensory: Olfactory, retina, ear Unipolar neurons - Fused dendrites and axon - Sensory receptors of the general senses (touch) Similar- Compare and contrast the three fundamental types of neurons based on function.
Afferent neurons - Detect changes in body or environment - Transmit information to CNS - Mostly unipolar Interneurons/association neurons - Lie between sensory and motor pathways - funciton - Mostly multipolar Efferent neurons - Transmit information from CNS out to PNS and effectors - Mostly multipolar Influence of blocking the central nervous system on the ability to respond to a particular stimulus. D, the CNS contains the brain and spinal cord which serve an integrative function in decision making for response to stimuli. How could you tell if a neuron had the property of secretion? the neuron would release acetylcholine. This secretion would takes place after the neuron goes through the two prior properties, including excitability and conductivity What is the physiologic significance of a dendrite?
dendrites are the information receiving processes of the neuron and are receptor proteins for binding to external chemical messages. The dendrites are shorter and more numbers than the axon. ___Influence of blocking slow axonal transport on the ability of a neuron to move proteins towards the soma.
No change. Slow axonal transport is anterograde transport; retrograde transport would move the axon towards the soma. This type of axonal transport is used to move large compounds. Influence of removing motor neurons on the ability of an individual to sense external stimuli. N, motor neurons carry efferent signals to effectors; sensory, afferent neurons carry sensory information from receptors to CNS. __Influence of destroying Schwann cells on the level of myelination in the CNS.
None, for CNS myelination oligodendrocytes are needed, while Schwann cells are needed for PNS myelination.
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__ influence of blocking voltage gated Ca2+ channels on the synaptic knob on the ability of the neuron to produce ACh A: N because the Ca2+ triggers the exocytosis of neurotransmitters such as ACh, ACh is produced in the soma, not the production of ACh.
What would happen if EPSP's underwent summation to a threshold level in the trigger zone? EPSPs are excitatory graded potential. If an excitatory graded potential reached threshold, an action potential would be generated.
Influence of having a lesion in the frontal lobe on the ability to recognize objects? Recognition of objects is coordinated by the temporal and occipital lobe. Not the frontal lobe.
What is the physiologic significance of the hypothalamus to the ANS? The hypothalamus is the major visceral motor control center in the ANS. It contains nuclei for primitive functions like hunger and thirst.
Influence of removing efferent neurons from a visceral reflex arc on the ability of the brain to detect internal stimuli. N, No change. Introceptors detect internal stimuli and the efferent neurons carry the motor signals to effectors.
How could you tell if the median and lateral apertures were clogged? The cerebrospinal fluid could not be drained. The apertures connect the fourth ventricle to the subarachnoid space. What is the physiologic significance of the limbic system? the limbic system provides storing of emotions and memory arousal along with behavior. For example a first kiss. What would happen to an EEG if the individual being monitored experienced extreme emotional stress? the EEG would show brain waves similar to Theta Waves indicating that they are experiencing emotional stress. What would happen to an EEG if the individual being monitored experienced extreme emotional stress?
hapter 6 Bone Tissue Study Guide
Functions and Structure of Bone
Describe the 6 functions of the skeletal system. Support- Structural framework and point of attachment. Physical protection- Internal organs, brain, spinal cord. Movement-anchor for skeletal muscles, provides leverage Electrolyte balance-ca2+&po4- storage Hematopoiesis (in red bone marrow) produce red (transport 02) and yellow(immunity) cells and platelets. Triglyceride storage in the yellow bone marrow Compare and contrast the two different types of bone tissue. osseous tissue and compact bone tissue and spongy bone tissue. Both types consist of the same kinds of cells, but the cells have different arrangements in the 2 types of bone. As a result, compact bone is smooth and dense, whereas spongy bone is porous and light. compact bone makes up the outer layer of bones, whereas spongy bone is found inside many bones Classify bones
according to their shapes and know a specific example of each type. Long bones
- longer than wide, levers acted upon by muscles ex. humerus and femur Short-
width=length glide across one another in multiple directions ex. carpals, tarsals
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Flat bone
-usually not flat but curved, muscle attachment and protection of soft organs ex. sternum and ribs irregular
-do not fit in other categories ex, vertebrae sphenoid sesamoid bone
- develop in tendons in response to friction, vary among individual's ex patellae Histology of Bone Tissue
List and describe the four different cells of osseous tissues. Compare and contrast each. Osteoblasts, osteocytes, osteoclasts, osteogenic stem cells osteogenic stem cells and osteoblasts are both found in the endosteum and periosteum, osteogenic and osteocytes are all bone building cells. However, osteocytes are found in the matrix and osteoclasts develop in the bone marrow and reside in the pits that they ate into the bone. However, all these cell types are found in osseous tissue Identify the most abundant organic and inorganic components of the matrix of bone and know the significance to each as it relates to bone as a composite. Matrix consists of fibers and ground substance, 15% water, 30% organic proteins majority is collagen also glycosaminoglycans, proteoglycans and glycoprotein whose functions are to provide strength and resilience, resist tension and provide flexibility and 55% mineral stats (calcium phosphate) and its function is to resist compression and support weight w/o sagging. Describe the histology of compact bone, be able to draw and label. Compact bone is dense and composed of osteons, while spongy bone is less dense and made up of trabeculae. Compare and contrast the structure of compact and spongy bone. compact bone is dense and composed of osteons, white spongy bone is less dense and made up of trabecculae . both compact and spongy bone contain proteins like collagens and osteoid which mineralize to help bone formation Compare and contrast red and yellow bone marrow. Redbone marrow produces blood cells whereas yellow bone marrow is responsible for storing fats, both red and yellow bone marrow can be found in long bones Bone Formation
Compare and contrast intramembranous and endochondral ossification. (This may be helpful if you learn the steps of each process). intermembranous ossification, bone develops directly from sheets of mesenchymal CT in endochondral ossification, bone develops by replacing hyaline cartilage however both mechanisms are essential for healing bone fractures. Describe the process of intramembranous ossification. 1. development of ossification centers and matrix mesenchyme cells cluster together and differentiate into osteogenic stems cells 2.calcification- osteoblasts enclose themselbes in matrix becoming osteocytes 3.formation of trabecula/ spongy bone- growth of multipe ossification centers forms "swiss cheese' like trabecular spongy bone Describe the process of endochondral ossification. 1
. development of cartilage model - mesenchymal stem cells differentiate into chondroblasts
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2
.growth of cartilage model- chondrocytes proliferate increasing length of cartilage model. periphery of cartilage starts to calcify, central chondrocytes undergo hypertrophy (enlarge and die) 3
. development of medullary cavity-osteoblasts in the diaphysis begin to create bone, periosteum forms, disintegrating cartilage towards ends of diaphysis provide space for growth of primary ossification. 4
.development of medullary cavity- completion of diaphysis formation and osteoclast activity create medullary cavity 5
. development of secondary ossification center- time of birth, spongy bone remains the center, no medullary cavity in epiphyses 6
.formation of articular cartilage and epiphyseal plate- removing hyaline cartilage becomes articulator cartilage, epiphyseal plate. Describe how the medullary cavity is initially formed during endochondral ossification. Sentence Central Chondrocyte's undergo hypertrophy (enlarged and die) from being cut off from nutrients and due to great size, they create the medullary cavity in the middle of the model. Describe the extent of long bone growth at the time of birth. Development of secondary ossification centers, formation of ossification centers in the epiphyses. Time of birth, spongy bone remains in the center. No medullary cavity in epiphyses. Compare and contrast the two cartilages found in/on the epiphyses at the completion of endochondral ossification. The two types of cartilage found at the end of endochondral ossification are articular cartilage and hyaline cartilage both types of cartilage contain hyaline cartilage differ in that while hyaline cartilage stays, articular cartilage is formed from it on the ends of of epiphyses to form a bumper in the joints Describe the process of bone lengthening. increased size of the cartilage pushes the epiphyses away from the diaphysis causing remodeling of the growth shaft making the bone longer Describe the process of bone growth in width. Osteoblasts in the periosteum form compact bone around the external bone surface. At the same time, osteoclasts in the endosteum break down bone on the internal bone surface, around the medullary cavity. Describe bone remodeling. Bones are remodeled through resorption of old bone and deposition of new bone, the architecture of bone is determined by mechanical stresses. List and describe factors that influence bone growth. Minerals such as calcium and phosphorus ions regulates the activation of osteoblasts and osteoclasts to facilitate bone regeneration, Vitamins such as A stimulates activity of osteblasts. Hormones such as GH, IGFs, TH and insulin stimulate osteoblast cell division. Physiology of Osseous Tissue
Describe bone mineralization. What are calcification inhibitors?
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Bone mineralization, the process by which the organic bone matrix becomes filled with calcium phosphate nanocrystals
, How do osteoclasts dissolve bone? Osteoclasts dissolve bone mineral by massive acid secretion Describe the consequences of calcium and phosphate ion imbalances. Disorders of calcium and phosphorus metabolism occur when calcium and phosphorus levels in the body deviate from basal condition, which could be classified into hypercalcemia, hypocalcemia, hyperphosphatemia, and hypophosphatemia
. Describe calcitriol, including its function and synthesis pathway. Calcitriol is vitamin D, and its function is raises blood calcium, increases intestinal absorption, promote urinary reabsorption of calcium ions also increases resorption from the skeleton. Environmental factor is the sun, 1.UV radiation causes keratinocytes to convert cholesterol into cholecalciferol 2. liver converts cholecalciferol into calcitriol 3. kidneys convert calcitriol into calcitriol Compare and contrast calcitonin & parathyroid hormone, including; where they are produced, how they affect blood calcium levels, and the mechanisms they use to change blood calcium levels. Calcitonin is a hormone that your thyroid gland makes and releases to help regulate calcium levels in your blood by decreasing it. Calcitonin opposes the actions of the parathyroid hormone, which is a hormone that increases your blood calcium levels Bone Fracture and Aging
Describe different types of fractures. Simple Fracture
Also called closed fractures, they occur when your bone suffers breakage but does not pierce through the epidermis. Compound Fracture
It is opposite to simple fracture and is also known as an open fracture. There will be buxation of the bone and it will pierce through the epidermis. So it is more likely to develop an infection in this type of a fracture. Oblique Fracture
In this type of fracture, the fissure runs diagonal to the axis of your bone. They are basically slanted fractures caused by an intense force applied at an oblique angle. Transverse Fracture
This fracture is perpendicular to the axis of the bone. You get a transverse fracture when something applies serious force at a right angle to the bone. Spiral Fracture
You have a spiral fracture when the fracture line twists around the bone. You get this type of fracture because of severe twisting force applied to the bone. Comminuted Fracture
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Among all different types of fractures, comminuted fracture is a serious one. The bone will be broken into several fragments. This is a highly complicated injury and usually heals quite slowly. Linear Fracture
You have this type of fracture when the break is parallel to the long axis of the bone. Greenstick Fracture
More common in children, it is partial fracture with one side of the bone unharmed. There will be torsion on the other side of the bone though. This type of fracture usually heals quickly Impacted Fracture
This type of closed fracture occurs when there is too much pressure on two extremities of the bone. The bone splits into two fragments-the fragments will jam into each other. Complete and Incomplete Fractures
You have a complete fracture if the bone is fragmented completely. It is an incomplete fracture when the two pieces of the bone partially avulse from each other-there will be some connection left between the both. Compression Fracture You develop a compression fracture when at least two bones are forced against one another. You usually get it in the bones of the spine usually due to a collapse of the anterior portion of the vertebra or advanced osteoporosis. Avulsion Fracture
This closed fracture occurs when you break a bone due to a forceful contraction of a muscle. It is more common in athletes and people who start their workout without spending time in warm-ups. Stress Fracture
It is also called hairline fracture. You develop this type of fracture in joints that you use too often. It is an overuse injure and is more common in athletes, ballet dancers, runners, and basketball players. Displaced Fracture
Among the many different types of fractures, this type occurs when your bone breaks into two parts in a way that the bone loses its alignment. Non-Displaced Fracture
It is opposite to the displaced fracture. It means your bone snaps into two pieces but stays aligned. Fatigue Fracture
Your bone becomes traumatized because of mundane stressors which cause weakness over a period of time. Pathological Fracture
You develop this fracture when you have an underlying health condition, such as osteoporosis. You can also get pathological fractures if cancer cells spread to the bones. Describe the process of fracture repair. Step 1 Hematoma Formation. Step 2 Fibrocartilaginous Callus Formation Step 3 Bony Callus Formation Step 4 Bone Remodeling Hematoma Formation Description- Torn blood vessels hemorrhage, forming a mass of clotted blood. Inflames.
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Fibrocartilaginous Callus Formation Description- Fibroblasts invade the fracture site and produce collagen fibers bridging the broken ends of the bone. Bony Callus Formation Description- Osteoblasts begin to produce spongy bone trabeculae joining portions of the original bone fragments and ossifying it. Bone Remodeling Description -
Osteoclasts begin to remodify the bone to the appropriate size and shape. Describe osteoporosis. a bone disease that develops when bone mineral density and bone mass decreases, or when the quality or structure of bone changes
. This can lead to a decrease in bone strength that can increase the risk of broken bones (fractures). Why are females more susceptible to osteoporosis? the hormone changes that happen at the menopause directly affect bone density
. The female hormone oestrogen is essential for healthy bones. After the menopause, oestrogen levels fall. This can lead to a rapid decrease in bone density. STUDY QUESTIONS
Functions and Structure of Bone
What is the physiologic significance of the skeletal system? The skeletal system consists of bones, cartilage and joints., ligaments. The anchor bones to each other, period. The skeletal system Provides support, Call my physical protection. Of the brain, spinal cord, and other internal organs. It acts as an anchor for skeletal muscles as well as providing leverage for those muscles, electrolyte balance. By storing electrolytes. As well as production of blood cells in red bone marrow and triglyceride storage in yellow bone marrow. How could you tell if you were observing osseous tissue? Osseous tissue is also called bone tissue. It is very dense and made of cells called osteocytes. Osseous tissue has a matrix hardened by minerals such as calcium phosphate and contains nerves and vasculature. As well as having pores like a sponge. What is the physiologic significance of flat bones? Flat bones are usually not flat, but curved. The physiological significance of these bones is attaching muscles and protection for soft organs. What would happen if the epiphyses of long bones were not enlarged? The epiphysis of long bones are enlarged to provide more surface area for attachments of tendons and ligaments for efficient movement. It also provides strength to joints, without enlargement tendons and ligaments do not have as much surface area to attach and movement is limited as well as the applied stresses on joints would be greater. Histology of Bone Tissue
What would happen if osteoblasts were selectively destroyed from a bone? The areas of the bones where the osteoblasts were destroyed would be weakened. The osteoblast secrete the extracellular matrix (Collagen parentheses) which then calcifies, giving the bone Tensile strength. What is the physiologic significance of collagen in bone matrix?
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Collagen provides strength and resilience., resist tension, gives flexibility. Without collagen, the bone would become brittle. What is the physiologic significance of bone being a composite? Since bones are composed of different types of materials, such as organic materials that provide flexibility and strength. As well as resilience. And mineral salts that resist compression and support weight without sagging. All of these materials work together to give the bonus rigidity and flexibility. ___ Influence of removing canaliculi on the ability for osteoclasts to communicate? No change, removing canalicula I would not affect the ability for osteoplastic. Indicate. Osteocytes are found in the lacunae that communicate through the Canaliculi for bone modeling and building density. How could you tell if bone tissue was spongy or compact? Compact bone, also known as cortical bone, borders spongy bone. In comparison to spongy bone, it is smooth, firm and heavy. It is white, whereas spongy bone is pink. ___ Influence of removing yellow bone marrow on the ability of the immune system to fight infection. No change, The yellow bone marrow does not play a role in the immune system or fighting off infection. Yellow bone marrow is a fatty marrow of the long bone. Red bone marrow is hematopoietic and plays a role in the immune system. Bone Formation
What would happen if intramembranous ossification failed? intramembranous Ossification is essential for bone development because it produces spongy bone that is remolded to form compact Flat bone. flat bone would not form and would not provide shape, structure or protection for the tissues and organs forming in the fetus and it would not form blood cells which takes place in the
Red bone marrow of flat bones without these bones the fetus would not survive. ___ Influence of preventing ossification center formation during intramembranous ossification on the chances of having brain damage as an adult hit on the head. ossification centers are where mesenchyme stem cells differentiate into osteoblasts that create the matrix of the bone during intramembranous ossification that forms flat bones such as cranial bones. ___ Influence of selectively destroying chondrocytes in an embryo on the probability of successful endochondral ossification. Decrease, during endochondral ossification, chondroblast create cartilage matrix and chondrocytes proliferate, increasing the length of cartilage model and later undergo hypertrophy and die, creating the medullary cavity in the middle of the model. Destroying them would mean long bones would not produce compact and spongy bone from cartilage in order to complete the endochondral process of bone formation. What is the physiologic significance of hypertrophy and hyperplasia of chondrocytes for endochondral ossification? Step two of endochondral ossification is the growth of cartilage. The chondrocytes in the middle of the cartilage undergo proliferation and hyperplasia to increase the length of the cartilage model. Then central chondrocytes undergo hypertrophy and grow in size, then die from being cut off of nutrients due to great size. This is what eventually forms the medullary cavity and the diaphysis of long bones. What would happen if secondary ossification centers could not form during endochondral ossification?
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Chondrocytes and ethicists die > secondary ossification center forms > Allows migration of osteoblasts into ephesis > Osteoblast creates spongy bone> Provides integrity to emphasis and space for bone marrow> Residual cartilage between the epiphysis and diaphysis becomes the epiphyseal plate allowing bone lengthening. How could you tell if epiphyseal cartilage was articular cartilage or the epiphyseal plate? Articular cartilage is the bumper on long bones and is located at the end of the bone, whereas the epithelial plate is sandwiched between spongy bone and cartilage. ____ Influence of premature closing of an epiphyseal plate on an individual’s height. Decrease The official plate, also known as the growth plate, contains hyaline cartilage, where chondrocyte hypertrophy and hyperplasia lengthen the bone. With the epithelial plate closes prematurely, the individual will be shorter than their genetic potential. What is the physiologic significance of hypertrophy and hyperplasia of chondrocytes for bone lengthening? Step 2 of E.O. is the growth of the cartilage model. The chondrocytes in the middle of the cartilage undergo proliferation hyperplasia to increase the length of the cartilage model. Then central chondrocytes undergo hypertrophy and grow in size/enlarge then die from being cut off of nutrients due to great size. This is what eventually forms the medullary cavity in the diaphysis of long bones. What would happen if osteoblasts could not dissolve bone during appositional growth? Nothing osteoblast build bone. What would happen if osteoclasts were more active than osteoblasts, during bone remodeling
? There would be more bone absorption than normal, which can lead to a decrease in bone strength that can increase the risk of fractures. ____ Influence of eliminating vitamin C from an individual on bone remodeling. NC Vitamin C is needed for synthesis of collagen. Collagen isn't used in the bone remodeling, it is only taken in by enzymes. Physiology of Osseous Tissue
What would happen if a non-bone tissue did not have calcification inhibitors? NONBone tissues do not have calcification inhibitors that result in abnormal calcification. ____ Influence of preventing hydrogen secretion from osteoclasts on their ability to dissolve bone. Decrease hydrogen ions combined with chloride ions to form hydrochloric acid. Which dissolves bone. No hydrogen secretion=no hydrogen chloric acid =no dissolving. ____ Influence of hypercalcemia on the likelihood of tetany. Decrease Hypercalcemia causes muscle weakness and sluggish reflexes due to excessive calcium, which decreases the likelihood. Of Tetany. Which is muscle spasms due to weak muscles. ____ Influence of increased calcitriol production on blood calcium levels. Increase calcitonin (Vitamin D ) raises blood calcium levels. ____ Influence of cutaneous exposure to UV radiation on the ability to produce parathyroid hormone.
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No change. UV radiation causes keratinocytes to convert cholesterol into cholecalciferol. parathyroid hormone is produced by the parathyroid gland when blood calcium is low and raises blood calcium levels. ____ Influence of destroying the liver on calcium homeostasis. Decrease the liver converts cholecalciferol into calcitriol> Converted from calcitriol into calciferol by kidneys. No liver> No Calcitriol Leads to children developing rickets and adults developing osteomalacia. Without calcitriol. What would happen if calcitonin was over-produced? Calcitonin decreases calcium levels by blocking the breakdown of bone calcium and by preventing kidneys from reabsorbing calcium can lead to hypercalcemia
Bone Fracture and Aging
How could you tell if fracture repair was in the hematoma formation or bony callus formation phase? Hematoma formation is the first phase of a fracture repair producing. The blood vessels that pass through the fracture line are broken, so, the blood leaking from the torn ends of the vessels, forms a mass of blood around the fracture. While the bony callus formation, is a reparative phase, in areas close to healthy, well-vascularized bone tissue, where osteoprogenitor cells become osteoblasts, producing spongy bone trabeculae, allowing the bone to heal with the time, turning the fibrocartilage into spongy bone and callus. ___ Influence of inefficient bone remodeling on the time needed to heal a bone fracture. when a fracture does not under go proper bone remodeling then the spongy bone will not be replaced by compact bone. How could you tell if an individual had osteoporosis? If the individual had a broken bone, back pain or hunched foreward. What leads to this is lack of exercise, not enough calcium, and the decrease of estrogen. The density of the bone decreases and becomes brittle that makes the bones easy to break. Osteoporosis a lot of time not found until the time of a broken bone What would happen to bone tissue if a woman ran out of eggs? Women with low levels of estrogen have an increased risk of developing weak and brittle bones (osteoporosis), which are more likely to break than healthy bones. Treppe
-The gradual increase in muscular contraction following rapidly repeated stimulation
-Calcium is pupled out each time, but when comng back in it get strong until reaching its maxiumum tention level.
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Wave stimulation
individual muscle contractions build on top of one another
-Each successesive twitch gets stronger because there is increasing Calcium in the sacroplasm, there is not enough time to in between stimuli to pump is all back in into the sacroplasmic reticulum
incomplete tetanus
During incoplete tetnus stimulus frequncy is going up with breif periods of rest until it reaches its maximum tention where it will plateau while still having breif priods of rest all through out this stimulation
Complete tetnus
-During complete tetnus the stimulation frequency is so high that the relatation phase it eliminated and than tention plateaus at a max level.
-It shoots up reaches is maxium tention for a couple seconds and than shoots back down
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