Practice Exam
First midterm exam, chapters 1 - 10.

True or False Questions

1. The central nervous system consists of the brain and spinal cord. (Chapter 1)
   T F

2. The telencephalon and diencephalon are the two main divisions of the forebrain. (Chapter 1)
   T F

3. The three main divisions of the hindbrain are the cerebellum, basal ganglia, and hypothalamus. (Chapter 1)
   T F

4. During embryogenesis, the notochord induces the formation of the neuroectoderm in the overlying ectoderm. (Chapter 2)
   T F

5. The peripheral nervous system develops from the cells of the neural tube. (Chapter 2)
   T F

6. At the equilibrium potential for a permeant ion, the flux of the ion down its concentration gradient is equal to the flux of the ion down the electrical gradient across the membrane. (Chapter 3)
   T F

7. If pNa were greater than pK, the resting membrane potential of a cell would closer to the sodium equilibrium potential than to the potassium equilibrium potential. (Chapter 3)
   T F

8. During the undershoot of the action potential, the membrane potential moves closer to the potassium equilibrium potential than at the resting potential because sodium permeability has returned to its resting level while potassium permeability remains elevated for a brief time after the action potential. (Chapter 4)
   T F

9. During the repolarizing phase of the action potential, the two mechanisms of repolarization are the closing of potassium channel n gates and the opening of the sodium channel m gates. (Chapter 4)
   T F

10. Neurotransmitter is released from a presynaptic terminal by a process of exocytosis, when synaptic vesicles fuse with the plasma membrane of the synaptic terminal in response to calcium influx. (Chapter 5)
    T F

11. A neurotransmitter that opens chloride channels in the postsynaptic cell would produce an excitatory postsynaptic potential. (Chapter 5)
    T F

12. Nociceptors respond to painful stimuli. (Chapter 6)
    T F

13. The receptive field of a secondary sensory neuron is the always the same as the receptive field of the primary sensory receptors from which the secondary neuron receives synaptic input. (Chapter 6)
    T F

14. In the somatosensory system concerned with muscle senses, the muscle spindle receptors give information about muscle length, whereas the receptors of Golgi tendon organs give information about muscle tension. (Chapter 7)
    T F

15. The main spinal cord pathway for ascending information about pain and temperature is the lateral sensory tract.
    (Chapter 7)
    T F

16. In the retina, both the photoreceptors and the horizontal cells are depolarized in darkness and hyperpolarize in response to illumination. (Chapter 8)
    T F

17. The neurons of the primary visual cortex have center-surround receptive fields. (Chapter 8)
    T F

18. The first auditory relay station in the brain is the cochlear nucleus, which is organized in a spatial representation of sound frequency, called a tonotopic map. (Chapter 9)
    T F

19. All hair cells of the cochlea respond best to low-frequency sounds (<1000 Hz). (Chapter 9)
    T F

20. Olfactory receptor cells have axons that project directly to the brain without intervening synapses.
    (Chapter 10)
    T F

21. G-proteins are involved in the linkage between the chemical stimulus and the change in ionic permeability in sweet and bitter taste transduction, but not in salt and sour taste transduction. (Chapter 10)
    T F

Multiple Choice Questions

22. During development of the nervous system (Chapter 2):
    1. the neuroectoderm is induced during gastrulation in the part of the ectoderm overlying the notochord.
    2. the cells of the peripheral nervous system arise from the neural crest.
    3. the neural tube gives rise to the central nervous system.
    4. all of the above are correct.
    5. none of the above is correct.

23. Suppose that in a neuron, the sodium equilibrium potential is +58 mV, the potassium equilibrium potential is -80 mV, and the resting membrane potential of the neuron is -70 mV. (Chapter 3)
    1. In this neuron, the potassium permeability of the membrane is less than the sodium permeability.
    2. If the sodium permeability and the potassium permeability were both doubled, the resting membrane potential of the neuron would remain at -70 mV.
    3. In this neuron, the internal potassium concentration is less than the external potassium concentration.
    4. In this neuron, both sodium and potassium are at equilibrium at the resting membrane potential of the cell.
    5. In this neuron, the membrane is permeable to potassium but not to sodium.

24. During an action potential (Chapter 4)
    1. the membrane potential at the peak of the action potential is close to the sodium equilibrium potential.
    2. the upstroke (depolarizing phase) of the action potential is produced by a large increase in sodium permeability as voltage-dependent sodium channels open.
    3. the refractory period corresponds to the period after an action potential when voltage-dependent potassium channels remain open, moving the membrane potential nearer to the potassium equilibrium potential.
    4. a and b, but not c.
    5. a, b, and c.

25. Regarding synaptic transmission, which of the following statements is not correct? (Chapter 5)
    1. Neurotransmitter release is triggered by calcium influx through voltage-sensitive calcium channels, which open in response to the depolarization produced by the arrival of an action potential in the synaptic terminal.
    2. Neurotransmitter is released from the synaptic terminal by exocytosis, when synaptic vesicles fuse with the plasma membrane of the terminal.
    3. An inhibitory neurotransmitter produces inhibition of a postsynaptic neuron by preventing excitatory neurotransmitters from binding to their receptors at excitatory synapses onto the postsynaptic neuron.
    4. An excitatory postsynaptic potential could be produced by a neurotransmitter that opens nonspecific cation channels that are equally permeable to sodium and potassium ions.
    5. The postsynaptic action of a neurotransmitter is mediated by neurotransmitter receptor molecules in the postsynaptic membrane, which bind the neurotransmitter and either directly or indirectly alter the ionic permeability of the postsynaptic cell.

26. In a primary sensory receptor cell (Chapter 6):
    1. the receptor potential is the change in membrane potential produced by synaptic inputs from neighboring receptor cells.
    2. sensory transduction is required for generation of a receptor potential only in exteroceptors, and not in interoceptors.
    3. lateral inhibition refers to the fact that sensory stimuli outside the receptive field inhibit the receptor cell, whereas sensory stimuli within the receptive field excite the receptor cell.
    4. receptive fields always have a center-surround organization, with opposite responses from the center and surround.
    5. the receptive field is the region of the sensory surface where a sensory stimulus affects the membrane potential of the receptor.

27. In the somatosensory system, which of the following statements is not correct (Chapter 7):
    1. all the axons of primary sensory receptor cells terminate locally in the spinal cord and do not send branches into the brain.
    2. the primary somatosensory cortex is located in the postcentral gyrus of the cerebral cortex.
    3. the ascending axons of neurons that carry information about touch, pressure, vibration, and proprioception to the brain are found mostly in the dorsal columns of the spinal cord.
    4. the ascending sensory axons of the dorsal columns leave the spinal cord and terminate in the dorsal column nuclei of the medulla, the gracile nucleus and the cuneate nucleus.
    5. the three major spinal pathways for ascending sensory information are the dorsal columns, the lateral sensory tract, and the spinocerebellar tract.

28. In photoreceptors of the retina, illumination causes the cells to hyperpolarize because (Chapter 8):
    1. rhodopsin directly binds to sodium channels in the plasma membrane and causes the channels to close.
    2. the G-protein transducin is activated when rhodopsin absorbs light, and activated transducin binds to and opens potassium channels in the plasma membrane.
    3. illumination causes the level of the second messenger, cGMP, to decline inside the cell, and cGMP directly binds to and opens nonspecific cation channels in the plasma membrane.
    4. all of the above are correct.
    5. none of the above is correct.

29. In the auditory system (Chapter 9):
    1. hair cells of the cochlea have axons that project directly to the brain in the auditory nerve.
    2. the hair cells of the cochlea make synapses onto neurons of the spiral ganglion.
    3. hair cells of the cochlea hyperpolarize in response to high-frequency sound stimuli and depolarize in response to low-frequency sound stimuli.
    4. all of the above.
    5. none of the above.

30. In the olfactory system (Chapter 10):
    1. primary olfactory receptor neurons have axons that project directly to the brain, where they make synapses onto neurons of the olfactory bulb.
    2. olfactory stimuli depolarize primary olfactory receptor neurons by means of G-protein-coupled receptor molecules located in the cilia of the receptor neurons.
    3. each glomerulus in the olfactory bulb receives synaptic inputs from the primary olfactory receptor neurons of one particular type, among the thousand or so different types of receptor cell found in the olfactory epithelium.
    4. all of the above.
    5. none of the above.