Human Anatomy and Physiology II
Exam 1, Version 5 - Feb. 16, 1996
Dr. Chabot
Multiple Choice (@2 points): Circle the letter of the one best answer. GOOD LUCK!
Answer only 30 out of 33! The first 30 answered will be graded.
1. At rest, approximately what percent of our oxygen intake is consumed by the brain?
A. 10%
B. 20%
C. 30%
D. 50%
2. When an action potential passes over the surface of a synaptic knob, the contents of vesicles are released in response to the presence of
A. calcium ions
B. sodium ions
C. neurotransmitters
D. neuropeptides
3. Assume that an axon is artificially stimulated about halfway along its length. Which of the following will occur?
A. Negative organic (Pr-) ions move out of the cytoplasm to the outside of the axon.
B. The impulse may travel in both directions.
C. Sodium ions cross the membrane out of the cytoplasm; potassium ions move across the membrane into the cytoplasm of the axon.
D. Negative feedback loop will occur causing Na+ channels to close.
4. Where would you look in the spinal cord for the cell bodies of motor neurons?
A. ventral gray horn
B. lateral gray horn
C. white matter
D. dorsal root ganglion
5. A nerve cell membrane may become depolarized as a result of
A. unequal distribution of ions on each side of the membrane
B. some ion channels being opened while others are closed
C. the relative ease with which potassium ions diffuse through membranes
D. totally preventing sodium ions from passing through the membrane
6. Which of the following glial cells is not found in the CNS?
A. oligodendrocytes
B. schwann cells
C. astrocytes
D. ependymal cells
7. Neurotransmitters are produced and packaged in the soma (cell body) and are taken to the terminals via:
A. simple diffusion
B. axonal transport
C. channels opening and closing
D. all of the above
8. The units used to measure the resting potential of a nerve fiber are
A. watts
B. millivolts
C. millimeters
D. calories
9. Postsynaptic potentials:
I. can be summed.
II. are graded.
III. are conducted decrementally (decrease in amplitude with distance).
IV. usually last much longer than action potentials.
A. I and III only
B. II and IV only
C. I, II, and III only
D. I, II, III, and IV
10. When an inhibitory neurotransmitter combines with a receptor site on a postsynaptic membrane, the first event that is triggered is an:
A. influx (inward flow) of potassium ions.
B. influx of sodium ions.
C. influx of chloride ions.
D. efflux (outward flow) of potassium ions.
11. Saltatory conduction
A. occurs only if the myelin sheath is continuous
B. occurs only if nodes of Ranvier are lacking
C. is faster than conduction on an unmyelinated fiber
D. is slower than conduction on an unmyelinated fiber
12. If a series of post synaptic potentials that sum is not great enough to surpass the threshold level at the axon hillock, the strength of the action potential generated will be:
A. zero.
B. proportional to the strength of the post synaptic potentials.
C. inversely proportional to the strength of the post synaptic potentials.
D. the same, no matter what the strength of the post synaptic potentials
13. Hyperpolarization of the neuronal membrane may be produced by any factor that:
A. increases the membrane's permeability to sodium ions.
B. decreases the membrane's permeability to sodium ions.
C. stimulates the sodium-potassium pump.
D. increases the membrane's permeability to potassium ions.
14. The dorsal root of each spinal nerve:
I. carries sensory information from peripheral receptors.
II. contains the processes (axons/dendrites) of nerve cells located in ganglia.
III. contains motor neuron cell bodies.
A. I only
B. II only
C. III only
D. none of the above
15. Two neurons X and Y have excitatory input onto neuron Z. The terminal of neuron X is located 1.5 mm from the axon hillock of neuron Z, while the terminal of neuron Y is located 3.0 mm from the hillock. If, at different times, both X and Y stimulate neuron Z at the same rate and cause the same amount of post-synaptic depolarization at the terminals:
A. Neuron X will have a lesser chance of causing neuron Z to fire
B. Neuron Y will have a lesser chance of causing neuron Z to fire
C. They will both cause neuron Z to fire since action potentials are all-or-none
D. They both have an equal chance to cause neuron Z to fire.
16. In the crossed extensor reflex initiated on the left side, the motor neurons of the right biceps will:
A. not be affected
B. be stimulated by excitatory interneurons
C. be inhibited by inhibitory interneurons
D. be inhibited by neurons of the thalamus
17. TEA, a neurotoxin, blocks:
A. the active transport pump which maintains ion gradients
B. K+ channels
C. Na+ channels
D. Cl- channels
18. Sensory information from receptors in the body travels up the spinal cord to the brain along the:
A. spinocerebellar tract
B. rubrospinal tract
C. corticospinal tract
D. none of the above
19. Glial cells:
A. are found in higher numbers in the central nervous system than even neurons
B. function to insulate axons
C. are found in the gray matter of spinal cords
D. all of the above
20. Sodium and potassium ion channel selectivity appears to be based on:
A. different charges on the ions
B. channel recognition factor
C. the fact that one is a salt
D. size differences between channels
21. Masses of cell bodies and dendrites appear _____ in the spinal cord.
A. white
B. gray
C. brown
D. transparent
22. Relative refractory refers to
A. an all or none action potential
B. the time after an action potential during which a neuron is less sensitive to stimulus
C. your cousins who work in an automobile assembly plant
D. the fact that neurons are rapidly repolarized
23. Approximately 3 msec after an axon is strongly depolarized:
A. all the K+ channels are closed.
B. the Na+ channels open.
C. the Na+ channels are inactivated.
D. the K+ channels are inactivated.
E. none of the above
24. During an action potential
A. a small percentage of the total number of Na ions diffuse into the cell
B. a small percentage of the total number of K ions diffuse out of the cell
C. a large percentage of the total number of Na ions diffuse into the cell
D. a large percentage of the total number of K ions diffuse out of the cell
E. A and B only
F. C and D only
25. Which of the following is not true about an action potential in a nerve cell?
A. It is normally caused by a sudden increase in sodium-potassium pump activity.
B. It is associated with a sudden increase in sodium permeability (gates open) and a somewhat slower increase in potassium permeability (gates open).
C. It can occur in a neuron because of the unequal distribution of ions across the membrane.
D. It does not vary in amplitude with the strength of the stimulus used to trigger it.
26. Which of the following are descending tracts in the spinal cord?
A. the spinothalamic
B. the spinocerebellar
C. the corticospinal
D. none of these
27. After an action potential, the nerve cell membrane re-develops a resting potential and
A. potassium channels in the membrane open and potassium ions diffuse outward
B. a wave of action potentials travels the length of the nerve fiber as a nerve impulse
C. sodium channels in the membrane open and sodium ions diffuse inward
D. ion channels close and the membrane becomes less permeable to sodium and potassium
28. The patellar tendon reflex involves:
A. stimulation of the quadriceps muscle
B. an interneuron
C. a motor neuron
D. A and C only
E. all of the above
29. Neurons have different nutritional requirements than other cells in that they
A. require glucose as a source of ATP
B. require fatty acids as a source of ATP
C. require O2 as a source of ATP
D. all of the above
E. none of the above
30. Ion pumps are important for which of the following?
A. long term maintenance of the resting potential
B. short term maintenance of the resting potential
C. long term maintenance of the action potential
D. short term maintenance of the action potential
31. Neurons are different than other cells because they lack:
A. endoplasmic reticulum
B. a nucleus
C. golgi apparatus
D. mitochondria
E. None of the above
32. The effects that a neurotransmitter will have on the postsynaptic membrane is determined primarily by:
A. the chemical structure of the transmitter
B. the type of pre-synaptic cell
C. the types of enzymes located in the synapse
D. the structure of the post-synaptic receptor
33. Which of the following are not known to be neurotransmitters:
A. ACh
B. norepinephrine
C. amino acids
D. proteins
E. none of the above
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FILL-INS (@2 points):
Complete the following sentences with the most appropriate (one) word.
Choose 10 out of 12 only.
1. The difference in electrical charge between the inside and outside of a polarized nerve cell membrane is
called the _______________________ _________________________.
2. A(an) __________________ is the junction between the parts of two neurons.
3. The ____________________ root of a spinal nerve consists entirely of sensory neuron axons.
4. There are approximately ________________________ pairs of spinal nerves.
5. A __________________ is a predictable, involuntary response to a stimulus.
6. Descending motor information descends in the spinal cord in the _______________tract.
7. Proteins which allow ions to pass through membranes only after they are stimulated by chemical messengers are called ________________.
8. An inhibitory chemical messenger at the synapse is known as __________________.
9. The ionic basis for the resting and action potentials was first worked out in the __________ giant axon.
10. The additive effects of EPSPs caused by the same synapse is known as _______________________ summation.
11. The cells that help to insulate axons in the central nervous system are ________________________.
12. Norepinephrine is removed from the synapse via _________________________________.
Essay/Short Answer (@ 10 pts). Answer only 2 of the following 3. The first 2 answered will be graded.
1) Draw and label a diagram showing a cross section through the spinal cord. Be sure to label at least two "tracts"
2) Draw and label one or two graphs showing the principle of temporal and spatial summation. Hint: You should probably also include a drawing that indicates where the inputs are located on the post-synaptic cell.
3) Draw and label a neuronal cell membrane and the inside and outside concentrations of important ions.