BIO 201 Chapter 11 Muscular System assignment OPS

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Central Arizona College *

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201

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Mechanical Engineering

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Dec 6, 2023

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Page 1 Chapter 11-The Muscular System OPS For this assignment, please read the chapter and answer the questions below. Please type your answers in red or blue color. Please note that points may be deducted if answers are not submitted in these colors. Sentences in italics are meant to help you understand the material- they are not questions Each question is worth .05 points. This assignment is worth 28 points. Skeletal Muscle Mechanics All muscles have at least two points of attachment. Define the following terms - (1 point) Origin – The end of the muscle attached to a fixed (stabilized) bone. Insertion - The moveable end of the muscle that attaches to the bone being pulled. The origin is typically proximal to the insertion when the body is in anatomical position. When complex movements occur, muscles commonly work in groups rather than individually. Their cooperation improves the efficiency of a particular movement. For example, large muscles of the limbs produce flexion or extension over an extended range of motion. Define the following terms as they refer to muscles - (2 points) Agonist- a muscle that produces a particular movement, also called the prime mover. Antagonist- opposes the movement of a particular antagonist. Synergists- a smaller muscle that assists a larger antagonist. Fixators- a type of synergist that stabilizes the bone that is the attachment for the prime mover’s origin. Define the following terms- as they refer to fascicle organization - (3.5 points) Circular – A type of fascicle organization where the fascicles are arranged in concentric rings. Convergent- A type of fascicle organization where the fascicles converge from a broad origin to a single tendon insertion.

Page 2 Parallel- a type of fascicle organization where the fascicles run parallel to the long axis of the muscle. Pennate- a type of fascicle organization where fascicles are short and attach obliquely to a central tendon. Unipennate- a type of pennate muscle where all the muscle fibers are on the same side of the tendon. Bipennate- a type of pennate muscle where the muscle fibers are on both sides of the tendon 2. Multipennate- a type of pennate muscle where the fascicles insert into multiple tendons tapering towards a common tendon 2. Muscle Mechanics: Lever Systems The operation of most skeletal muscles involves the use of leverage and a lever system. Define the following terms : ( 2 points ) Lever – a rigid rod (usually a length of bone) that turns about a pivot (usually a joint). Fulcrum- the pivot point around which a lever rotates. Effort- the force or muscular contraction applied to move or stabilize a body part or perform a specific action. Load- the resistance or external force encountered by a muscle or joint during movement or a specific physical task. In the human body, joints are the fulcrums, your bones act as levers, and your muscle provide the effort. Levers can operate in one of two ways. Define each way: (1 point) Power lever- A power lever is used to gain a mechanical advantage, where the effort force needed is less than the load force. Speed lever- A speed lever is used to magnify movement.

Page 3 Depending on the relative positions of the three elements (effort, fulcrum, and load), a lever belongs to one of three classes. Define each type -( 1.5 points) First-class lever- is characterized by the fulcrum (pivot point), load (resistance), and effort applied (muscular force) arranged in a way that the fulcrum is positioned between the load and the effort, as seen in the neck when nodding the head. Second-class lever- the load is positioned between the fulcrum and the effort applied, as seen when rising up on your toes, with the ankle joint serving as the fulcrum, the body weight as the resistance (load), and the calf muscles applying the force (effort). Third-class lever- the effort applied (muscular force) located between the fulcrum and the load, such as the flexion of the elbow joint when lifting a weight, with the elbow joint as the fulcrum, the hand-held weight as the load, and the bicep muscles as the effort. For each muscle action listed below, define the term and state the term that has the opposite meaning. (5 points) 1. Flexion: decreasing the angle between two bones (bending). Opposite: Extension - increasing the angle between two bones (straightening a bend). 2. Abduction: moving away from the body's midline. Opposite: Adduction - moving toward the body's midline. 3. Circumduction: circular movement of a limb or extremity. Opposite: there is no opposite to circumduction. 4. Pronation: rotation of the forearm so the palm faces down or backward. Opposite: Supination - rotation of the forearm so the palm faces up or forward. 5. Planter flexion: movement at the ankle joint that points the foot downward away from the leg. Opposite: Dorsiflexion - movement at the ankle joint that brings the foot closer to the shin.

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Page 4 What is hyperextension? Name one joint that can be hyperextended. ( 1 point ) Hyperextension refers to the extension of a joint beyond its normal range of motion. An example of a joint that can be hyperextended is the knee. What is hyperflexion? Name one joint that can be hyperflexed. ( 1 point ) Hyperflexion refers to excessive flexion of a joint. An example of a joint that can be hyperflexed is the neck. Name four criteria used in naming muscles and provide an example that illustrates each criterion. ( 2 points ) a. Shape: the names of some muscles reflect their shape. For example, the deltoid muscle is roughly triangular, with delta being the Greek word for triangle. b. Size: muscles can be named based on their size relative to other muscles in the same area. For example, the gluteus maximus is the largest muscle in the buttock region. c. Location: muscles can be named based on their location in the body or the bones with which they are associated. For example, the tibialis anterior is located near the tibia bone in the lower leg. d. Action: muscles can be named based on their primary action. For example, the abductor muscles of the thigh bring the leg toward the midline of the body. Which muscles act to move food down the length of esophagus ? (.5 point) Smooth muscles. Name the 4 muscles that act together to compress the abdominal contents . How does their muscle fiber arrangement contribute to the strength of the abdominal wall? ( 2 points ) a. Rectus abdominis is a long muscle that runs vertically along the front of the abdomen. It has a sheath-like covering made up of connective tissues called the rectus sheath. The fibers of this muscle run straight up and down, which allows it to flex your trunk forward. b. The external oblique muscle is located on each side of your rectus abdominis. Its fibers run diagonally downward and inward toward your midline. When these muscles contract, they help you bend forward and twist your trunk. c. The internal oblique muscle is located just inside your hip bones. Its fibers run diagonally upward and inward toward your midline. When these muscles contract, they help you bend forward and twist your trunk.

Page 5 d. The transversus abdominis muscle is located deep within the abdomen, beneath the internal obliques. Its fibers run horizontally across the abdomen. When this muscle contracts, it compresses your abdominal contents. Name the muscles of the rotator cuff. (2 points) a. Supraspinatus b. Infraspinatus c. Teres Minor d. Subscapularis Name the muscles of the quadriceps group in the leg. ( 2 points ) a. rectus femoris b. vastus lateralis c. vastus intermedius d. vastus medialis Name the muscles of the hamstrings group in the leg. (1.5 points) a. biceps femoris b. semitendinosus c. semimembranosus