e They are involved with complex processing of sensory by T8QqX451

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									     DO NOT HAND IN THIS PORTION OF THE EXAM - HAND IN THE SCANTRON FORM ONLY
Physiology 1                                           Test 2                                            Fall 2000
1. The receptive field of an afferent neuron
     a) refers to the number of interneurons with which the central process of the afferent neuron makes synaptic
        contact via divergence.
     b) refers to that part of the somatosensory cortex, that, when stimulated by a specific stimulus, gives rise to
        graded potentials in the receptors of that part of the cortex.
     c) is determined by the number of branches of the peripheral terminals of that neuron.
     d) is determined by the motor neuron and all the fibers it innervates.
     e) none of these are correct
2. Which of the following statements regarding the precision of locating a somatic stimulus is true?
     a) The precision is greater in areas of the body that have small, overlapping receptive fields than in areas
        with large, non-overlapping receptive fields.
     b) The precision is greater in the lips and fingers than on the back.
     c) The precision is greater for the skin than for the internal organs.
     d) a, b and c are correct
     e) none of these are correct
     Matching: Match the terms below with the most appropriate answer:
     a) tectorial membrane, b) tympanic membrane, c) cochlear duct, d) organ of Corti, e) utricle
3.   sensory structure in vestibular apparatus
4.   ear drum
5.   overlays the hair cells of the organ of Corti
6.   “sits” on the basilar membrane in the cochlea
7. is continuous in both the cochlea and vestibular apparatus
8. Which of the following is not true regarding cortical association areas?
     a)   They may receive sensory information directly from primary sensory areas.
     b)   They may receive sensory information directly from the thalamus.
     c)   They may integrate two or more types of sensory information.
     d)   They are found in each lobe of the cerebral cortex.
     e)   They are involved with complex processing of sensory information.
9. Receptors for the chemical senses are located in the
     a)   organ of Corti and the saccule.
     b)   cochlea and lateral geniculate nucleus.
     c)   skin and tendons.
     d)   tongue and nose.
     e)   fovea and the semicircular canals.
10. Which of the following is correct and important for determining stimulus intensity?
     a)   The magnitude of receptor potentials increases with increasing stimulus intensity
     b)   The frequency of receptor potentials increases with increasing stimulus intensity.
     c)   The magnitude of action potentials increases with increasing stimulus intensity.
     d)   The frequency of action potentials in second-order neurons in the ascending pathway increases as a
          result of recruitment of nearby receptor units.
11. Accommodation responses for near vision
     a)   include increased sympathetic stimulation of iris smooth muscle.
     b)   include relaxation of ciliary muscles to allow rounding of the lens.
     c)   include increased parasympathetic stimulation of the ciliary muscles.
     d)   are inhibited by application of acetylcholine agonists to the eye.
12. When light strikes a photoreceptor, the level of cyclic GMP
     a) increases and sodium channels open
     b) decreases and sodium channels close


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Physiology 1                                            Test 2                                             Fall 2000
    c) decreases and sodium channels open
    d) increases and sodium channels close
13. Which of the following could influence the concentration of a hormone in blood?
    a)   Rates of secretion, excretion and metabolic conversion of the hormone.
    b)   The concentration of a specific binding protein for the hormone.
    c)   The functional state of the liver or kidneys.
    d)   all of these
14. Removal of the adrenal cortices (plural of "cortex") would result in
    a) Decreased blood concentrations of cortisol and aldosterone, and increased concentrations of CRH and
       ACTH.
    b) Decreased blood concentrations of epinephrine and norepinephrine, and no change in concentrations of
       CRH and ACTH.
    c) Decreased blood concentrations of thyroid hormones, and increased concentrations of TRH and TSH.
    d) Increased blood concentrations of cortisol and aldosterone, and decreased concentrations of CRH and
       ACTH.
    e) Decreased blood concentrations of prolactin.
15. Regarding the structure and synthesis of hormones:
    a) Steroid hormones are synthesized from cholesterol.
    b) Thyroid hormones are catecholamines.
    c) The hormones of the adrenal cortex have the same structure as the neurotransmitters of adrenergic
       neurons.
    d) Most peptide hormones require binding proteins for transport in the blood.
    e) Vasopressin is synthesized in the adenohypophysis.
16. A hormone may be
    a)   inactivated by its effector cell.
    b)   activated by its effector cell.
    c)   inactivated by noneffector cells.
    d)   excreted before it has a chance to act on a effector cell.
    e)   all of the above.
17. The main differences between the modes of action of peptide hormones and steroid hormones are:
    a) Peptide hormones bind to intracellular receptors whereas steroid hormones bind to receptors on the cell
       surface.
    b) Peptide hormones bind to receptors in the nucleus whereas steroid hormones bind to receptors in the
       cytosol.
    c) Peptide hormones bind to receptors on the cell surface whereas steroid hormones act as second
       messengers.
    d) Peptide hormones bind to receptors on the cell surface whereas steroid hormones bind to intracellular
       receptors.
    e) There are no differences: both act by binding to receptors on the cell surface.
    The answers to question 18 – 20 are: a) True, b) False
18. The concentration of a hormone in the blood can affect the number of receptors for that hormone on or in a
    target cell.
19. Thyroid hormones exert a permissive effect on the actions of epinephrine.
20. Unlike neurons, endocrine cells generally do not act as integrators of various kinds of positive or negative
    inputs.
Comparisons: The answer is “a” if the answer on the left is the greater, “b” if the answer on the right is the greater
and “c” if the answers are the same.
                                  Left                                                   Right
21.      The role of ATP in muscle contraction being            The role of ATP in muscle contraction being
         energizing of the myosin cross-bridge                  detaching the cross-bridge binding
22.      Presence of troponin in skeletal muscle                Presence of troponin in smooth muscle


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Physiology 1                                             Test 2                                                Fall 2000
23.        Troponin being directly stimulated by calcium ion       Troponin being directly inhibited by calcium ion
24.        Production of ATP by glycolysis                         Production of ATP by oxidative phosporylation
25.        Skeletal muscle fiber type being determined by          Skeletal muscle fiber type being determined by type
           speed of contraction and method of synthesizing         of troponin and method of catabolizing glycogen
           ATP
26. The removal of calcium ions from the cytosol of skeletal muscle causes
    a) the myosin-binding sites on actin to be uncovered by tropomyosin.
    b) tropomyosin to change conformation and thereby move troponin molecules over cross-bridge binding
       sites.
    c) troponin to change conformation and thereby expose cross-bridge binding sites.
    d) the myosin-binding sites on actin to be covered by tropomyosin.
    e) none of the above.
27. During an isometric contraction of a skeletal muscle,
    a) sarcomere length does not change.
    b) the I bands shorten and the A bands stay the same length.
    c) the thick and thin filaments slide past each other.
    d) the M line is obliterated.
    e) cross-bridge binding does not occur
28. Which of the following statements regarding skeletal-muscle contraction is true?
    a) The tension developed during the contraction of a muscle fiber is dependent upon the initial length of the
       myosin molecules.
    b) There is a positive correlation between muscle-fiber length at the beginning of a contraction and the
       tension that can be developed by the fiber: the longer the fiber, the greater the tension.
    c) There is a positive correlation between the frequency of action potentials in a single muscle fiber and the
       tension it can develop: the greater the frequency, the greater the tension, up to a plateau.
29. Fast-glycolytic muscle fibers differ from slow-oxidative fibers in that
      a) the fast-glycolytic fibers rely on creatine phosphate as an ATP source for the first few seconds of
         contraction whereas the slow-oxidative fibers do not.
      b) the fast-glycolytic fibers have a smaller diameter than the slow-oxidative fibers.
      c) the fast-glycolytic fibers can generate greater maximal tension than the slow-oxidative fibers.
      d) the fast-glycolytic fibers generate less lactic acid than do the slow-oxidative fibers.
      e) the fast-glycolytic fibers can convert myoglobin to ATP.
30. Which of the following statements regarding skeletal muscle is true?
      a) A given skeletal-muscle fiber will contract when excitatory nervous stimuli sufficiently exceed inhibitory
         nervous stimuli at the cell body of the motor neuron that innervates that fiber.
      b) A given skeletal-muscle fiber will contract when excitatory nervous stimuli sufficiently exceed inhibitory
         nervous stimuli at the motor end plate.
      c) Skeletal-muscle fibers are joined together by gap junctions.
      d) Some skeletal-muscle fibers have pacemaker activity.
31. Smooth muscle contraction is mediated by the phosphorylation of ____________, which occurs as a result of
    a chain of biochemical events including the binding of calcium ion to ____________.
      a)   ADP / calmodulin.
      b)   Calmodulin / myosin.
      c)   actin / tropomyosin.
      d)   myosin / troponin.
      e)   myosin / calmodulin.
32. A major difference between smooth muscle and skeletal muscle is that
      a)   myosin is the regulatory protein in smooth muscle.
      b)   myosin is the regulatory protein in skeletal muscle.
      c)   skeletal muscle may exhibit spontaneous activity.
      d)   only skeletal muscle requires increased calcium ion concentration in the cytosol for contraction.
33. According to the hierarchy of motor control,


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Physiology 1                                           Test 2                                            Fall 2000
    a) the highest level of control consists entirely of areas of cerebral cortex.
    b) the middle level of control contains no areas of cerebral cortex.
    c) the lowest level of control includes the cerebellum and basal ganglia.
    d) structures in the middle level receive information from both the highest and the lowest levels of the
       hierarchy.
    e) afferent information from skin, joint and muscle receptors has little influence on body movement.
34. Reflexes triggered by the activation of muscle spindles
    a)   have a monosynaptic component.
    b)   result in activation of alpha and gamma motor neurons.
    c)   result in the contraction of muscle spindle fibers.
    d)   include the "knee jerk" reflex.
    e)   all of the above are correct
35. The intrafusal fibers in a muscle spindle
    a)   are not true muscle fibers because they cannot contract.
    b)   are innervated by alpha motor neurons.
    c)   function to maintain tension on spindle receptors.
    d)   are much like some smooth muscle that responds by contracting by being stretched.
36. Which of the following statements regarding control of body movement is correct?
    a)   The basal ganglia receive input from dopaminergic neurons of the substantia nigra.
    b)   The cerebellum is important for the initiation of body movement.
    c)   The basal ganglia form part of the corticospinal pathways.
    d)   The skeletal muscles of the body are represented in the primary motor cortex proportionately to their size.
    e)   None of the above.
37. Which of the following is not true of corticospinal fibers? They
    a)   generally affect large groups of muscles.
    b)   may synapse directly on alpha motor neurons.
    c)   may synapse directly on gamma motor neurons.
    d)   may synapse directly on interneurons.
    e)   may synapse with afferent neurons in ascending pathways.
38. Unlike long-term memory, working memory
    a)   has limited capacity.
    b)   exists in the form of either graded or action potentials.
    c)   can be disrupted by drugs, electroconvulsive shock, or a blow to the head.
    d)   does not have as many “categories to characterize it
    e)   all of these are correct
39. EEG arousal is the recording of brain activity of someone who has just been awakened from sleep.
    a) True, b) False
40. The EEG tracing of a relaxed individual who has closed eyes and is not concentrating on anything in particular
    is mainly an alpha rhythm.
    a) True, b) False




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                                       Hand in this portion of the test
Name:__________________________________________                  Objective         Problems         Essays         Total
                                                                             /40              /10            /25           /75

Physiology 1                                        Test 2 - Part II                                               Fall 2000
Problems: Show your work including unit cancellations, where appropriate. No work, no credit.
1. An action potential is being propagated at a rate of 325 miles/hour. How fast is that in metric units
   (kilometers/hour)? There are 2.54 cm/inch and 1,760 yards in a mile. Or, there are 0.621 mile/km. 2 points
2. What is the surface to volume ratio of a cube 2.85 mm on a side? 1 points
3. A certain physiology class tested their thresholds to tasting salt and sugar. The majority of students could
   taste sugar at 0.004 M and taste salt at 0.02 M. How much more sensitive to sugar is the class than to salt?
   1 points
4. An individual has been smoking an average of 3 packs of cigarette a day for forty (40) years. If a package of
   cigarettes contains twenty (20) cigarettes, and assuming a year is 365 days, how many cigarettes has this
   person smoked? 2 points
5. A giant cubodial epithelial cell is measured at 0.12 mm on a side. What is its surface to volume ratio? 2 point
6. Assuming that a quail egg is spherical and that its radius (r) is 2.04 mm, what is its surface to volume ratio? 2
   points [Surface area = 4r and Volume = 4/3r and  = 3.14]
                             2                      3




Bonus question - 5 points.
A researcher wondered if the scale effect (S/V) also applied to the circumference of a circle versus its cross
sectional area. She computed the surface area and circumference of various sized circles and got the following
result. What should she conclude and why?

              Radius                     1             2          3            4              5
              Circumference                  6.28      12.56      18.84        25.12              31.4
              Cross Sectional Area           3.14      12.56      28.26        50.24              78.5
              S/V Ratio

Explanation




Essays: These questions are expected to be answered using complete sentences and correct grammar.
Abbreviations should be defined the first time they are used.
1. Explain how stimulus intensity is coded in sensory neurons. 5 points
2. Explain the process of signal transduction by which the photoreceptor cells transduce light into action
   potentials. 5 points


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Physiology 1                                           Test 2                                             Fall 2000
3. Contrast and describe the locations of receptors for the various classes of hormones. 5 points
4. List, in order of occurrence, the events of the contraction cycle of skeletal muscle. Start with the action
   potential arriving at the motor end plate. 5 points
5. Write an essay that explains the surface to volume phenomenon (scale effect) to a bright twelve year old and
   its implications for biology. 5 points




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