Exam 2- Winter 2003 MPP3202

Exam 2- Winter 2003 MPP3202 - DCT—BB—EBBS 15:24 HEHLTH...

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Unformatted text preview: DCT—BB—EBBS 15:24 HEHLTH SCIENCE LIBRHRY 5738841421 P 81/18 Student name: —,_,—._.—a—-—'—— Student number: —_—_————— TA name: Thurs/Fri Lab _—__n—‘_—_._.———-— ELEMENTS OF PHYSIOLOGY 2nd Examination March 12, 2003 Fill in the top of this page. Include your TA's name and lab day on this page. We need only your name and TA's name on the top of the answer sheet. You don't need to fill in any circles on the front of the answer sheet- Circle the letter of the one best answer for each question on the question sheet and fill in the appropriate answer circle on the answer sheet. (A=1, s=2, c=3, D=4. E=5) Each answer is worth 2 points. Turn in both the question and answer sheet. Staple the answer sheet to the back of the question sheet with the answer circles showing. 1. When a sciatic nerve of a frog is stimulated with an electrode both the flexors and extensors of the innervated leg are stimulated. Why is it, then, that the leg has an extensor response rather than a flexor response? A. Because the leg’s extensor muscles are stronger than its flexors. B. Because more neurons innervate extensors than felxors. C. Because flexors require stronger stimuli than do extensors. D. Because more Ca2+ is released in flexors than in extensors. 2. Which of the following occurs during the latent period of a skeletal muscle twitch? A. Depolarization travels along the transverse (T) tubules. B. Ca2+ is released from the sarcoplasmic reticulum. C. Tropomyosin's conformation changes. D. All the above occur during the latent period. 3. Which of the following spinal reflexes are in the correct order from shortest reaction time to longest? A. stretch (knee jerk) reflex, flexor (withdrawal) reflex, crossed extensor reflex B. flexor reflex, stretch reflex, crossed extensor reflex C. stretch reflex, crossed extensor reflex, flexor reflex c. flexcr reflex. crossed extensor reflex, stretch reflex Page 1 DCT—BB—EBBS 15:25 HEHLTH SCIENCE LIBRHRY 5738841421 P.82/lfl When a skeletal muscle is increasingly stetched the active force it deveops during a single twitch rises then falls. What is the most important factor that determines the force developed during a single twitch? A. The amount of Ca2+ released from the sarcoplasmic reticulum. B. The number of cross bridges formed between actin and myosin. C. The time required for Ca2+ reuptake by the sarcoplasmic reticulum. D. The diffusion time for the neurotransmitter to cross the myoneural junction. (recruitment) and wave What is the difference between quantal summation or temporal summation (fusion of responses)? A. Greater force can be generated by wave summation than by quantal summation. B. Wave summation requires more stimuli than does quantal summation. C. Wave summation takes longer to develop than does guantal summation. D. All the above distinguish quantal and wave summation. Which of the following describe neurons? A. They are the basic unit of a nervous system. B. They receive and integrate input from other neurons. C. They generate and conduct action potentials. D. They communicate with other cells. E. All the above characterize neurons. Which statement best characterizes the nerve terminal at the end of the axon? A. It receives input from other neurons. B. It generates and conducts action potentials. C. It is the site of neurotransmitter secretion. D. All the above describe a nerve terminal. Which of the following has the fastest conduction velocity? A. a small diameter, unmyelinated neuron B. a small diameter, myelinated neuron C. a large diameter,myelinated neuron D. a large diameter, unmyelinated neuron Which of the following best describes the nodes of Ranvier? areas of axons rich in voltage—gated Na+ channels. A. They are E. They are areas of dendrites that receive input from other cells. C. They are the site of neurotransmitter synthesis and storage. D. They are present in neurons with the lowest conduction velocities. Page 2 DCT-EB-EEEE 15:25 10. ll. 12. 13. HEHLTH SCIENCE LIBRHRY 5738841421 Which of the following happens at a chemical synapse? A. B. C. D. E. A neurotransmitter is released from the presynaptic neuron. The neurotransmitter diffuses across the synaptic cleft. The neurotransmitter binds to a receptor on the postsynaptic cell. Ion channels on the postsynaptic membrane open in response to receptor occupation. All the above occur at a chemical synapse. How does synaptic transmission in the central nervous system differ from synaptic transmission at the nerve-skeletal muscle junction? A. B. D. In the central nervous system most synapses are electrical but the nerve—muscle synapse is chemical. Synaptic transmission in the central nervous system may be excitatory or inhibitory but at the nerve—muscle junction it's always excitatory. Input from a single neuron will usually depolarize a central nervous system cell but input from many motor neurons are needed to depolarize a muscle cell. All the above differentiate synaptic transmission in the central nervous system and at the nerve-muscle junction. The figure below represents the membrane potential of a neuron over time neuron.) a neurotransmitter. (The dashed line represents the threshold potential of the At the time indicated by the arrow the neuron was exposed to What is the most likely effect of the neurotransmitter on the neuron? MEMBRANE 5’ nu———————— _——fl+ll-I FoTENTIAL (mu J .;70 1" “TIME A. It opens Na+ channels. B. It closes Na+ channels. C. It opens K+ channels. D. It closes K+ channels. How is an electrical synapse best described? A. It has channels that allow ions to flow from one cell to another quickly in either direction. B. Its synaptic delay is longer than a chemical synapse but its effects are more prolonged. C. Its neurotransmitter is cleared by enzymatic degradation or by diffusion. D. There is no depolarization of the postsynaptic cell. Page 3 P.83/1E DCT-EB-EEEE 14. 15. 16. 17. 18. 15:25 HEHLTH SCIENCE LIBRHRY 5738841421 P.84/1E Botulinus toxin and nerve gases like phosgene both cause muscle paralysis but by different mechanisms. What statement best describes the effect of those agents on the neuromuscular junction? A. Botulinus toxin prevents release of acetylcholine so the muscle can't contract; phosgene prevents breakdown of acetylecholine so the muscle can't relax. B. Botulinus toxin prevents acetylcholine from binding to its receptor so the muscle can't contract; phosgene blocks Na+ channels so the muscle cell can't deplorize. C. Bctulinus toxin blocks voltage-gates Ca2+ ChannElEF Phosgene blOCks Na+ channels. D. None of the above describe the toxins' effects. What do single excitatory and inhibitory post synaptic potentials (EPSPS and IPSPs) have in common? A. They each produce small changes in membrane potential. B. They each produce graded membrane potentials. C. They each increase ion conductance in plasma membrane channels. D. EPSPs and IPSPs share all the above characteristics. During a spinal reflex one set of muscles is stimulated while the opposing set of muscles is kept from being activated. How are those opposing muscles kept from contracting? A. The motor neurons innervating the opposing muscles secrete an inhibitory neurotransmitter. B. The motor neurons innervating the opposing muscles are hyperpolarized by inhibitory post synaptic potentials from interneurons in the spinal cord. C. The motor neurons that stimulate muscles to contract send branches to the opposing muscles that hyperpolarize them. D. Stimulation of a muscle causes an increase in the threshold potential of opposing muscles so they are more difficult to depolarize. What would be the effect of a toxin that prevented the release of acetylcholine from nerve terminals? Skeletal muscles would not function. The parasympathetic nervous system would not function. . The sympathetic nervous system would not function. All the above would happen. c a m w What is the function of the semicircular canals and how many are there? . They sense linear motion and there are six of them. They sense angular motion and there are six of them. . They sense sound and there are two of them. They sense linear motion and there are four of them. 5 n w m Page 4 DCT—BB—EBBS 19. 20. 21. 22. 23. 24. 25. 26. 15:26 HEHLTH SCIENCE LIBRHRY 5738841421 What is the function of the organ of Corti? A. It converts variations in air pressure (density) in the outer ear to variations in fluid pressure in the inner ear. E. It detects stretch of the tendon attached to a muscle and initiates the stretch (knee jerk) reflex. C. It converts variations in fluid pressure in the inner ear to action potentials in an afferent nerve. D. It senses linear movements (up. down, forward.r back). E. It is the component of the retina that allows rods to recover after photobleaching. Which statement best describes cells with long, narrow stereocilia called hair cells? A. They are the sensory cells for the chemical senses taste and smell. B. They are cells of the retina responsible for color vision. C. They are found in the inner ear and mediate senses of hearing and motion. D. They are found in the spinal cord where they act as inhibitory interneurons. Which of the following is activated by riding an elevator? A. a semicircular canal B an occulomotor reflex C. an otolith organ D B and C but not A Are the following statements true or false? (Fill in circle #1 for true; #2 for false.) T F Of air vibrations having frequencies of BOHZ, 300Hz, 3,000Hz and 30,000 Hz the one at 3,000 Hz will be most sensitively detected by a human's ear. T F Changes in the amplitude of an air pressure wave are perceived as changes in the loudness of the sound. T F A gelatinous fluid containg CaCO3 crystals known as otoliths (ear stones) is characteristic of the semicircular canals. Sensory information that reaches consciousness is called sin) A. stimulus B. adequate stimulus C. sensation D. threshold Receptor potentials are ALWAYS A. all—or—none E. graded C. depolarizations D. hyperpolarizations Page 5 F.85/lfl DCT-EB-EEEE 15:26 HEHLTH SCIENCE LIBRHRY 5738841421 P.86/1E 27. The type of receptor that does not have an adequate stimulus is the A. thermoreceptor B. nociceptor C. chemoreceptor D. photoreceptor E. mechanoreceptor 28. The process by which all sensory receptors become less responsive to maintained stimuli over time is called A. adaptation B. lateral inhibition C. fatigue D. transduction 29. The order of events in sensory transduction is receptor potential ——3 action potential ——a stimulus stimulus ——} action potential -—3 receptor potential receptor potential e—P stimulus --> action PDtEntial stimulus ——e receptor potential ——e action potential action potential —-5 receptor potential r—e stimulus {30002175 30. The code that sensory centers in the brain use to distinguish differences in stimulus strength is based on the A. size of receptor potentials B. size of action potentials C. frequency of receptor potentials D. frequency of action potentials E. none of the above 31. The area of the nasal cavity where odorant receptors are located is the A. olfactory bulb B. olfactory epithelium C. glomerulus D. papilla 32. The optic disc is a "blind spot" on the retina because A. the image of a visible object never falls on the optic disc B. it is comprised of rods only C. it is comprised of cones only D. it contains no photoreceptors 33. The transparent part of the sclera is called the A. ciliary body B. aqueous humor C. cornea D. lens Page 6 DCT-EB-EEEE 15:27 HEHLTH SCIENCE LIERHRY 5738841421 PLET/la 34. Accommodation occurs in the A. lens only B. cornea only C. cornea and lens D. retina 35. As a visible object moves closer to a viewer, focus on the retina is maintained by increasing the distance between the lens and the retina decreasing the distance between the lens and the retina increasing the curvature of the lens decreasing the curvature of the lens o D O w W 36. In bright light, the pupil of the eye A. constricts because the circular iris muscle contracts B. constricts because the radial iris muscle contracts C. dilates because the circular iris muscle contracts D. dilates because the radial iris muscle contracts 37. Cone vision is more acute (resolves details) than red vision because CODES A. contain photopigments that are more sensitive to light than rod photopigments E. outnumber rods in the eye C. show much less convergence than rods D. are more concentrated in the peripheral retina than rods 38. Shortly after moving from a light to a dark environment vision is poor because A. the pupils are constricted B. the photopigments of the cones are bleached C. the photopigments of the rods are bleached D. accommodation has not occurred 39. In patients with myopia A. near objects are in focus B. far objects are out of focus C. the eyeball is too long for the lens system D. vision can be restored with a concave corrective lens E. all of the above 40. The receptor potential stimulated by light in the photoreceptor cell is a A. depolarization caused by the opening of sodium channels B. depolarization caused by the closing of sodium channels C. hyperpolarization caused by the opening of sodium channels D. hyperpolarization caused by the closing of sodium channels Page 7 DCT—BB—EBBS 41. 42. 43. 44. 45. 46. 15:27 HEHLTH SCIENCE LIBRHRY 5738841421 P.88/lfl Eye movements that prevent visual loss by moving the image to different sets of photoreceptors are called A. tracking movements B. chiasmatic movement C. saccadic movements D. accommodating movements The image of a visible object seen in the left half of the visual field stimulates the A. right side of each retina and is perceived in the left visual cortex 3. left side of each retina and is perceived in the left visual cortex C. left side of each retina and is perceived in the right visual cortex D. right side of each retina and is perceived in the right visual cortex Which attributes correspond to the sympathetic nervous system? A. short preganglionic fibers and the preganglionic neurotransmtter is norepinephrine. B. long preganlionic fibers and the preganglionic fibers secrete acetylcholine. C. short preganglionic fibers and the postganglionio neurotransmitter is norephinephrine. D. long postganglionic fibers and the postganglionic neurotransmitter is usually acetylcholine. In which structure is a muscarinic receptor important? A. parasympathetic postganglionic neurons B. sympathetic postganglionic neurons C. effector cells innervated by the parasympathetic division D. effector cells innervated by the sympathetic division During a "fight or flight" response, smooth muscle in airways of the lungs relax while smooth muscle in blood vessels of the small intestine contract. Why are their responses different? A. Airway smooth muscles have beta 2 receptors and intestine smooth muscles have beta 1 receptors. E. Airways are innervated by the parasympathetic division, while the intestines are innervated by the sympathetic division. C. Airway smooth muscles contain the same receptors as intestine smooth muscles but the neurotransmitters are different. D. Airway smooth muscles have M2 receptors and intestine smooth muscles have Ml receptors. Efferent signals exit the spinal cord throught the: A. dorsal root B. ventral root C. interneuron D. nocioeptor Page 8 DCT—BB—EBBS 47. 49. 50. In addition to the brain, 3:! D n m In the stretch 15:27 HEHLTH SCIENCE LIBRHRY 5738841421 interneurons are primarily located in the: white matter of the spinal cord dorsal root ganglion spinal nerve gray matter of the spinal cord (knee jerk) reflex: A. knee extensors are activated and knee flexcrs are inhibited B. knee extensors and knee flexors are activated C. knee extensors are inhibited and knee flexors are activated D. knee extensors and knee flexors are inhibited If you step on a tack and activate the crossed-extensor reflex, what happens? A. ipsilateral knee extensors are activated and contralateral knee flexors are inhibited B. ipsilateral knee flexors are activated and contralateral knee extensors are activated C. ipsilateral knee extensors are inhibited and contralateral knee extensors are inhibited D. ipsilateral knee flexors are inhibited and contralateral knee flexors are activated What is the function of the gamma motor neuron? It stimulates extrafusal fibers in skeletal muscle It stimulates intrafusal fibers in the muscle spindle It carries afferent signals from the muscle spindle to the spinal cord- It stimulates the flowwer spray endings Page 9 F.89/1B ULl—HU—dflflfi NO. in NO. on Q—ank Test. 11 11 11 11 11 11 11 11 11 11 11 ll 11 ll 11 11 11 11 11 11 11 11 11 11 21 21 21 21 21 21 21 21 21 21 21 21 21 21 21 21 21 21 IDKDLDLDmkDLO'Lfl 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 F’HPJFJH fltflhJFLOLDUJQEnU1filthH MIAPJF*HI4 Okfltnalmifl MMNM .bWNH [\JM G‘LLJ'I LIJLxwaLdeL-JUJLJLGNMN kflmeWLH-meI—‘meq shubn—bnhrhrb-l‘: OHU‘n-bLJMI—‘D bull-sh- LDCDaJ U1 0 lbidfi HtHLIH bthNLt LIHHHHT DYJUU414§1 Answer Key for Test‘ 3/11x2003 qurect Answg; A D A B D E C C A E B C A A D B D B C C D 1 1 2 C B B A D D B D C A C A C C E D C D C C A B D 11 E E Page 1 F.1U/lfl TDTHL P.1D ...
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Exam 2- Winter 2003 MPP3202 - DCT—BB—EBBS 15:24 HEHLTH...

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