BIOL 252
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Exam 1 – Spring 2011
Name _________________________
Multiple-choice questions: 40 @ 3 each = 120 points. Choose the best answer.
Short-answer questions: 1 @ 30 points.
I will return your graded Scantrons on Thursday and your essays next Tuesday.
My labs will also receive their practicals next Tuesday. Drs. Jones and Campbell will inform their lab
students about when their practicals will be returned.
Relax! Think! Excel!
Multiple-choice questions
1. The [Na+] inside a typical neuron is ___ than the [Na+] in the extracellular fluid.
a. greater than
b. less than
c. about the same as
You know the answer to this question. Now relax and do well on this exam.
2. Which of the following can be found only in the peripheral nervous system (PNS)?
a. axons within the corpus callosum
b. neuron cell bodies in the dorsal root ganglion
c. ependymal cells
d. oligodendrocytes
e. none of these
3. The neuronal pathway cartoon at right depicts a
___.
a. converging circuit
b. diverging circuit
c. parallel circuit
d. reverberating circuit
e. short circuit
4. Which of the following carries ONLY efferent information?
a. dorsal ramus
b. spinal nerve
c. ventral ramus
e. More than one of these carries only efferent information.
d. ventral root
• Use the following to answer the next three (3) questions:
a. astrocyte b. ependymal cell
c. microglial cell
d. oligodendrocyte
e. Schwann cell
5. One of this cell’s functions is to act as a phagocyte and clean up debris in the CNS.
6. This cell produces the myelin found within ascending and descending spinal cord tracts and columns.
7. An important function of this cell is its role in forming the blood-brain barrier.
8. The cell bodies of neurons found within the somatic sensory portion of the dorsal gray horn are ___.
a. heavenly bodies
b. interneuron cell bodies
c. motor neuron cell bodies
d. Schwann cell bodies
e. unipolar sensory neuron cell bodies
9. The telodendria and boutons of a resting neuron (i.e. one that is not transmitting an action potential)
is most permeable to which ion?
a. Ca2+
b. Clc. K+
d. Na+
e. The neuron’s telodendria and boutons are equally permeable to all ions.
10. If a drug prevented the opening of voltage-gated K+ channels and prevented the closing of voltagegated Na+ channel inactivation gates, then the “average” neuron’s membrane potential would remain at
about ___.
a. -60 mV
b. -90 mV
c. +30 mV
d. +66 mV
e. 0 mV
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Use the diagram at right to answer the next six (6) questions:
11. K+ is nearest to its equilibrium potential at
the point labeled ___.
a. Resting potential
b. 
c. ‚
d. ƒ
e. „
12. All Na+ leak channels are open nearest to the
point labeled ___.
a. 
b. ‚
c. ƒ
d. „
e. all of these
13. Voltage-gated Na+ channels are closed AND
inactivated nearest the point labeled ___.
a. Resting potential
b. 
c. ‚
d. ƒ
e. „
14. Voltage-gated K+ channels are opening
nearest to the point labeled ___.
a. Resting potential
b. 
c. ‚
d. ƒ
e. „
15. According to the figure at right, Na+
inactivation gates open and Na+ activation
gates close nearest the point labeled ___.
a. -40 mV
b. -60 mV
c. -70 mV
d. -90 mV
e. 0 mV
16. The depolarization that occurs nearest to the
point labeled  is most likely to be due to the
opening of ___.
a. a new Wal-Mart in your neighborhood
b. chemically-gated K+ channels
c. chemically-gated Na+ channels
d. voltage-gated K+ channels
e. voltage-gated Na+ channels
17. Action potentials are propagated at the slowest rate along axons that are ___.
a. large in diameter and myelinated
b. large in diameter and unmyelinated
c. small in diameter and myelinated
d. small in diameter and unmyelinated
18. Which of the following changes in membrane permeability would be expected to result in an
excitatory postsynaptic potential (EPSP)?
a. ↑ PNa+
b. ↑ PK+
c. ↑ PCld. ↑ PU
e. All of these would cause an EPSP.
19. If a neurotransmitter released at an axoaxonal synapse inhibited the opening of Ca2+ channels, ___.
a. an EPSP would always be produced in the postsynaptic cell
b. an IPSP would always be produced in the postsynaptic cell
c. less neurotransmitter would be released by the presynaptic cell
d. more Ca2+ would exit the presynaptic cell’s bouton
e. More than one of these is always true.
• Use the following to answer the next question:
My dog, Hektor, did some research again this weekend. Good boy! He found that the cell membranes
of neurons in the newly-discovered species, Membraneous unusualis, have the following characteristics:
o The concentration of the ion O+ is higher outside than inside these cells.
o The concentration of the ion I+ is higher inside than outside these cells.
o The inside of the cells’ membranes are negatively charged when compared to the outside of
the cells’ membranes.
20. If one of these neuron’s membranes suddenly became equally permeable to both O+ and I+, then
___ would cross the membrane most rapidly because ___.
a. I+; the electrochemical forces on I+ are in opposite directions
b. I+; the electrochemical forces on I+ are in the same direction
c. O+; the electrochemical forces on O+ are in the same direction
d. O+; the electrochemical forces on O+ are in opposite directions
e. none of these
21. Neurotransmitter (e.g. acetylcholine) is released as a direct result of the opening of voltage-gated
___ channels
a. Ca2+
b. Clc. K+
d. Na+
22. The direct effect of acetylcholine binding to its receptor is the opening of an ion channel. Therefore,
the acetylcholine receptor is classified as a metabotropic receptor.
a. true
b. false
23. The outermost covering of the spinal cord is known as the ___.
a. arachnoid membrane
b. dura mater
c. falx cerebri
d. pia mater
24. The connective tissue surrounding individual axons within a nerve fascicle is known as ___.
a. aquarium
b. endoneurium
c. epineurium
d. perineurium
e. terrarium
25. All sensory information enters the spinal cord through the ___.
a. dorsal ramus
b. dorsal root
c. rami communicantes
d. ventral ramus
e. ventral root
26. Spinal reflexes are fast, stereotypic responses to a particular stimulus. The fastest reflex pathways
contain the most synapses.
a. true
b. false
27. The conus medullaris in the typical adult human is located nearest to which vertebra?
a. C7
b. Cx5
c. L2
d. S3
e. T7
28. Which of the following tracts or columns conveys motor information?
a. anterior corticospinal tract
b. lateral spinocerebellar tract
c. lateral spinothalamic tract
d. posterior columns
e. No general principle allows me to answer this question.
29. Within a single spinal cord segment, how many interneurons are required for the flexor reflex?
a. 0
b. 1
c. 2
d. 3
e. 4
30. The knee-jerk (patellar or stretch) reflex is a(n) ___ reflex.
a. contralateral
b. cranial
c. monosynaptic
d. reciprocally-innervated
31. Gray matter within the spinal cord contains ___.
a. myelinated axons
b. neuron cell bodies
c. oligodendrocytes
d. Schwann cells
e. more than one of these
32. A dorsal root ganglion contains the cell bodies of ___ neurons.
a. bipolar, motor and sensory
b. multipolar, motor
c. multipolar, sensory
d. unipolar, motor
e. unipolar, sensory
33. Intrafusal fibers within a muscle spindle send action potentials to the spinal cord only when they are
being stretched.
a. true
b. false
34. The experiment we discussed in lecture that involved “decerebrate” cats demonstrated that ___.
a. no benefits to humans could possibly come from any research involving animals
b. people with spinal cord injuries cannot benefit from animal research
c. scientists enjoy torturing animals for no good reason
d. walking and other behaviors are based upon spinal reflexes
35. Somatic motor neurons are located in the ___.
a. dorsal gray horn
b. French horn
d. ventral gray horn
e. ventral root ganglion
c. lateral gray horn
36. Sensory information from both exteroceptors and interoceptors in the back travels toward the spinal
cord within the ___.
a. dorsal ramus
b. rami communicantes
c. ventral ramus
d. ventral root
37. Cutting the ventral ramus of a spinal nerve would destroy the ___.
a. axons of both motor and sensory neurons
b. axons of only motor neurons
c. axons of only sensory neurons
d. cell bodies of both motor and sensory neurons
e. cell bodies of interneurons
38. The minimum number of neurons required to form a spinal reflex arc is ___. (Checkpoint question)
a. 1
b. 2
c. 3
d. 4
e. 5
39. Rami communicantes directly connect sympathetic chain ganglia to the ___.
a. brain
b. dorsal rami
c. dorsal roots
d. ventral rami
e. ventral roots
40. In the lectures about reflexes, we discussed a guy who: (1) put is hand on a tack, (2) burned his
hand on a frying pan, (3) stepped on the tack while rushing to the sink to run cold water on his burn.
This guy must be a(n) ___.
a. Senator
b. Congressman
c. A&P professor
d. idiot (but I repeat myself)
e. Mark “e” on you Scantron. Really, the answer is “e”.
NAME_____________________________________________
Short-answer question
30 points
A. Clearly diagram the structure and function of a Flexor Reflex. Include ALL diagrammatic
information shown in Figure 13-19 AND label your diagram with the following ADDITIONAL terms:
anterior/ventral side of spinal cord
axon collaterals to other segments of spinal cord
dorsal horn
dorsal root
dorsal root ganglion
gray matter
interneuron cell bodies (label both)
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motor neuron cell bodies (label both)
pain receptor
posterior/dorsal side of spinal cord
sensory neuron cell body
white matter
ventral horn
ventral root
Use arrows to indicate the flow of information through this reflex arc.
Use appropriate symbols to indicate excitatory ( + ) and inhibitory ( - ) synapses.
CLEARLY indicate all synapses. For example, like this: o------------< o----------<
You will need to construct your own key. Be sure to define any abbreviations that you use.