Physiology Lecture Exam 2: Practice Questions and Review Guide

PHYSIOLOGY NAME: _________________________________ LECTURE EXAM #2 PRACTICE QUESTIONS Professor Sania Zaidi-Merchant NOTE: The following questions are some of the possible questions that can be asked on the lecture exam #2. This does not mean that these are the only possible questions. Anything discussed in lectures and present on power point chapter slides is a possible question on exam. Please make sure to study the chapters/lectures and then use this sheet to answer questions and test your knowledge of Physiology. Good Luck! 1. What is CNS and what is its function? CNS is brain and spinal cord. Responsible for receiving, processing, and responding to sensory info 2. What is PNS and what is its function? PNS is everything else besides brain and spinal cord. Relays all sensory info to CNS so it can respond accordingly. Made up of nerve cells (receptors) to respond to stimuli 3. What is the difference between neurons and neuroglia? Neurons are the fundamental units of the brain and nervous system since they generate and conduct electrical impulses by responding to stimuli. Neuroglia cells do not conduct electrical impulses, rather they protect, nourish, and insulate the neurons. 4. What is the difference between a bipolar and a multipolar neuron? Bipolar neurons have one dendrite and one axon attached to the cell body. Multipolar neurons have many dendrites and one axon. Bipolar can be found in ears + eyes. Multipolar is 80% majority. 5. What is the function of Schwann cells? Are they a part of the CNS or PNS? Insulation; help form myelin sheath. Part of PNS 6. What is meant by membrane potential? Electrical charge difference between in/out of cells due to distribution of ions 1

7. At rest, the membrane potential of a neuron is -70mV 8. At rest, it is more negative/positive inside the cell? Circle the correct answer. 9. During depolarization : a. Which channels open up? Voltage gated Na + channels b. What is the threshold potential? -55 mV c. What enters the cell? Na+ d. Is the inside of the cell more negative or positive? Positive 10. What happens during the repolarization phase of action potential? Explain At maximum positive voltage, Na + channels close and K + channels open and K + pushes out until voltage is negative again. Also known as returning to rest 11. Do action potentials travel faster or slower in unmyelinated neurons? Slower. Action potential travels faster in myelinated axons because myelin insulates the axon and assembles voltage-gated sodium channel clusters at discrete nodes along its length. 12. What is a neurotransmitter? a. Where is it produced and stored? Produced at presynaptic terminals/neurons. Stored in synaptic vesicles b. What is its function? Carry chemical signals from one neuron to the next target cell 13. What is the difference between an ionotropic and metabotropic receptor? Explain Ionotropic receptor (ion channel receptor) is where the receptor and channel are the same, they are also fast and direct. Metabotropic receptor (g-protein linked receptor) is where the receptor and channel are different proteins, they are slow. 2

14. What is a synapse? Connection between neurons 15. What is the difference between passive and gated ion channels? Gated ion channels stay closed and only open to a stimulus. Passive gated ion channels are always open 16. What are the 3 types of gated ion channels? Ligand (chemical) gated – open in response to binding with a chemical Voltage gated – open in response to changes in membrane potential Mechanically gated – open in response to mechanical vibrations such as touch or sound 17. What are tyrosine kinase receptors? Mediates cell to cell communication and controls cell growth, motility, differentiation, and metabolism 18. What are neuroglial cells? Where are they found? Neuroglial cells protect, nourish, and insulate neurons. Found in the CNS 19. Name two neuroglial cell in CNS and its function. Neurons: receive info from senses, process it, and send back messages to exert an action, all through an electrochemical process Oligodendrocytes: produce myelin that covers the neuronal axon and increases the speed of electrical impulses through the axon Microglia: immune cells that can “eat” the microbes that enter the CNS. Clean injured brain areas from cell debris Astrocytes: take care of neurons and participate in transmission of messages, cell metabolism and control of blood flow 20. What are the three layers/membranes surrounding the brain tissue? Dura mater, arachnoid mater, and pia mater 3

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21. What is corpus callosum? Major structure of the brain that connect the right & left cerebral hemisphere 22. What are the 3 regions of brain stem and their respective function? Midbrain: controls involuntary eye movement and reflexes related to visual and audio info Pons: relays messages from the cortex to cerebellum. Responsible for facial sensitivity. Plays major role in REM sleep where dreams occur Medulla oblongata: regulates heart rate, breathing, digestion and sleeping. Plays a role in regulating muscle tone and movement. Responsible for initiating reflexes like vomiting, swallowing, gagging, coughing, sneezing and hiccupping 23. What are white and gray matter composed of? How is the location of gray/white matter different in brain versus spinal cord? Gray matter: dendrite, soma, & unmyelinated axons White matter: myelinated axons Brain: gray matter on the outside, white matter on the inside Spinal Cord: gray matter on the inside, white matter on the outside 24. What is the function of frontal lobe of cerebrum? Muscle control, cognitive functions like concentration, planning, verbal communication, thinking 25. What is CSF? Where is it made (part of brain and cells)? Clear, colorless, watery fluid that flows in and around your brain and spinal cord. CSF is made in choroid plexus epithelium and ependymal cells of the ventricles. 26. What is a nociceptor? Receptor that responds to pain 4

27. Give an example of chemoreceptor in your body. Exteroceptor: smell -> odor molecules bind to chemoreceptors -> sends signal to brain Interceptor: BV, brain stem respond to CO 2 , O 2 , H + to maintain pH in body (7.35-745) -> regulate your breathing 28. What are baroreceptors? Where are they found in the body? Baroreceptors are mechanoreceptors that monitor blood pressure and volume. Located in BV near the heart 29. Explain the reflex arc from the reception of pain stimulus to the motor response (withdrawal reflex) by the body. 1. Stepping on glass stimulates pain receptors in right foot. 2. Action potentials are generated in afferent pathway , which propagates impulses to the spinal cord 3. Spinal cord is integrating center . Afferent neuron stimulates a. Excitatory interneurons – stimulate motor neurons to quads b. Inhibitory interneurons – inhibit motor neurons to hamstrings c. Interneurons that are part of the ascending pathway to brain 4. One efferent pathway stimulates quads to contract. Other efferent pathway leads to relaxation of hamstrings 5. The quads and hamstrings are effectors . Results in pulling away from painful item 30. What is a monosynaptic reflex? List all the components involved. Reflex pathway with only one synapse between the sensory and motor neuron. Components involved: receptor, afferent neuron, central component, and efferent neuron. 31. What is the function of ascending tracts? Be able to list the various ascending tracts and the sensory information they carry to CNS. Ascending tracts carry info (sensory) from PNS to the brain (up the spinal cord) Spinothalamic: anterolateral – sense of pain, temp, and touch Dorsal columns: fasciculus cuneatus & fasciculus gracilis – touch, pressure, & body position from skin, muscles, tendons, and joints Spinocerebellar: anterior & posterior: sensory info from golgi tendons and muscle spindles from posterior horn to cerebellum. Coordinated muscle contractions (movement) 5

32. List the descending motor tracts are associated with coordination of voluntary muscles? Pyramidal – voluntary and fine skilled movements. Split into 2 tracts: corticobulbar controls neck and head muscle movement, corticospinal moves limbs and trunk 33. What is the difference between afferent and efferent neurons? Afferent neurons are sensory neurons that carry nerve impulses from sensory stimuli towards the CNS, while efferent neurons are motor neurons that carry neural impulses away from the CNS and towards muscles to cause movement. 34. A neuron that carries sensory information from spinal cord to the thalamus is first/ second/third order neuron? Circle the correct answer. 35. What function does Somatic nervous system control? Is it a part of CNS or PNS? Controls skeletal muscles. Part of PNS 36. Sympathetic nervous system is a part of CNS or PNS? Circle the correct answer. 37. Sam had a large meal and his digestive system function has increased. Is this function under sympathetic or parasympathetic nervous control? Why or why not? This is under parasympathetic since known as rest and digest so it aids in digestion 38. How are sympathetic neurons different from parasympathetic neurons? Sympathetic: preganglionic neuron is short, postganglionic neuron is long. Parasympathetic: preganglionic neuron is long, postganglionic neuron is short 39. Cholinergic receptors bind to ACh 40. Epinephrine is considered a neurotransmitter and a hormone. Why? Explain Neurotransmitter since it can be released from a neuron to synapse Hormone since it can be released by gland to move through blood to an effector organ 6

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41. Cranial Nerve XII coordinates facial, motor. Muscles of the face 42. Which 3 cranial nerves are involved with movement of eye muscles? Oculomotor (CNIII), abducens(CNVI), trochlear (CNIV) 43. Which cranial nerve is involved in the sense of smell? CNI - olfaction 44. Which cranial nerve is associated with vision? CNII - optic 45. What are cholinergic receptors? Ionotropic (ligand gated ion channel) receptors 46. What are adrenergic receptors? G coupled receptors. Responsive to catecholamines 47. What are muscarinic receptors? Metabotropic (g-coupled) receptors 48. List the difference between sympathetic and parasympathetic nervous system neurons? Sympathetic: preganglionic neuron is short and located in thoracolumbar region, postganglionic neuron is long. Parasympathetic: preganglionic neuron is long and located in cranioscral region, postganglionic neuron is short 7

49. How are unencapsulated receptors different from encapsulated receptors? Give an example of each Unencapsulated receptors are dendrites that are not wrapped in connective tissue/glial cells. Ex: free nerve endings for pain and temp, tactile discs (Merkel cells) for light touch and texture, hair receptors monitor movement of hair Encapsulated receptor examples: Meissner corpuscles sense light touch and texture, Pacinian corpuscles sense deep pressure, stretch, tickle and vibration, ruffini corpuscles detect heavy touch, pressure, joint movements and skin stretching 50. What is a phasic receptor? A type of sensory receptor that is fast adapting and quick – i.e. smell 51. What is the function of gustatory cells? Specialized cells that aid in the sensation of taste 52. What is the function of basal cells? Stem cells that replace taste cells every 10 days – 2 weeks 53. How is the physiology of taste different for salty and sweet foods? Explain the different sensory mechanisms and pathway to the brain. When eating salty foods, the sodium enters the sodium channel and results in depolarization. From the depolarization, the voltage-gated calcium channels open. The increase in calcium causes neurotransmitters to be released. When eating sweet foods, the sweet substance binds to a receptor which causes conformation. After this, G-coupled proteins are activated which activates AC. AC converts ATP to cAMP. The cAMP activates a protein kinase that closes a potassium channel. This depolarizes the cell which opens voltage-gated calcium channels. The increase in calcium causes neurotransmitters to be released. The main difference is that with salty foods, sodium is able to enter the channel easily, while with sweet food, it needs to bind to a receptor which activates G proteins and second-messenger systems. 54. Which nerves carry the sensation of gustation from the mouth to the brain? Facial CNVII – collects sensory info from taste buds over anterior 2/3 of tongue Glossopharyngeal IX – posterior 1/3 of tongue 8

Vagus X – taste buds of palate, pharynx and epiglottis (minor role) 55. What are olfactory receptor cells? Chemoreceptors that allow you to smell. Found in a small patch of tissue high inside of nose 56. Where can you find tufted and mitral cells? What is their function? You can find them in glomeruli from olfactory tracts. They send signals to the brain 57. What is the function of the outer ear? Transmission of sound to inner ear 58. Name the three ossicles. Which part of the ear are they located in? Stapes, incus, malleus. Located in middle ear 59. What specific part of the ear is involved in hearing? Inner ear 60. Which chamber in the ear contains the organ of corti? Scala media 61. How are hair cells involved in hearing? Outer hair cells: sends/amplifies signals to send to inner hair cells Inner hair cells: connected to cochlear nerve -> brain 62. Where can you find endolymph? How is it different from perilymph? Endolymph is in the cochlear duct/scala media. Endolymph is only within scala media and is considered intracellular fluid. 9

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63. Explain the physiology of hearing once the vibrations are transmitted to the cochlea. Bending of basilar membraine -> fluid vibrations (endolymph) -> stereocilia of hair cells also bends -> nerve impulses (Aps) sent via cochlear nerve > temporal bone 64. What is conductive hearing loss? What part of the ear would be damaged in such a type of loss? Conductive hearing loss is when there is a decrease in the ability of sounds to move from the ear to the oval window. This can occur due to too much ear wax, a ruptured tympanic membrane, or the damage of the malleus/incus/stapes. 65. What part of the ear is responsible for equilibrium? The vestibular apparatus is composed of the utricle, saccule, and three semicircular ducts. 66. Name the 3 different layers of eye. Outer fibrous tunic – protects the eye (sclera, cornea) Middle vascular tunic – admits and focuses light (choroid, ciliary body, iris) Inner neural tunic – sensory nerves (retina) 67. What are rods and cones? What is their specific function in the eyes? Photoreceptors or light detecting/absorbing cells Rods – more sensitive to light, night/scotopic vision Cones – more sensitive to colors but not as sensitive to light, sharp visual acuity 68. What is the function of retinal ganglion neurons? Second-order neurons whose axons form optic nerve 69. What is hyperopia? How can it be corrected? Hyperopia is farsightedness, which means they can’t see close up. This occurs because the eyes are too short which causes the focal point of the image to be behind the retina. To fix this, you would need convex lenses. 10

70. What is color blindness? What cells are affected in this disease? Most common cause is genetic mutation of gene coding for cones (X-linked disorder) 71. What is a negative afterimage? The area of the retina that was desensitized by the bright image does not respond as well to this new light input as the rest of the retina. Instead, this area appears as a negative afterimage, a dark area that matches the original shape . The afterimage may remain for 30 seconds or longer. 72. What happens to the shape of the lens or as your eye tries to accommodate when looking at things at a distance? Lens becomes thin (flattens) 11

LECTURE EXAM 2 STUDY GUIDE

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