Chapter 5 : Neurohistology (3) Flashcards Preview

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Flashcards in Chapter 5 : Neurohistology (3) Deck (14):
1

1. Peripheral nerve fibers regenerate at the rate of
(A) 0.1 mm/day
(B) 3 mm/day
(C) 100 mm/day
(0) 200 mm/day
(E) 400 mm/day

1-B. Peripheral nerve fibers regenerate at the rate of 3 mm/day.

2

2. Fast pain has a conduction velocity of
(A) 1 m/sec
(B) 5 m/sec
(C) 15 m/sec
(D) 30 m/sec
(E) 100 m/sec

2-C. Fast pain has a nerve fiber (A delta) conduction velocity of 12-30 m/sec. Slow pain has a nerve lffier (C) conduction velocity of 0_5-2 m/sec.

3

3. A lO-year-old boy has severed his radial nerve. Which of the folIowing cells plays a rna¬jorrole in axonal regrowth?
(A) Fibrous astrocytes
(B) Fibroblasts
(C) Oligodendrocytes
(0) Protoplasmic astrocytes
(E) Schwann celIs

3-E. Schwann cells playa major role in axon regeneration (axon regrowth) in the peripheral nero
vous system (PNS).

4


4_ The muscle stretch reflex (MSR) is initiated by which of the following rtlCcptors?
(A) End bulbs of Krause
(B) Merkel disks
(C) Muscle spindles
(0) Ruffini end bulbs
(E) Vater-Pacini corpuscles

4-C. The muscle stretch reflex is initiated by muscle spindles.

5


5. All of the following statements concerning neurons are correct EXCEPT
(A) they are of neuroectodermal origin
(B) they have lost the capacity to undergo ceIl division
(C) they contain Nissl substance
(0) they are derived from the neural tube and . neural crest
(E) bipolar neurons are the most common type of neuron

5-E. Neurons are of ectodermal origin, contain Nissl substance, and have lost the capacity to undergo cell division. The neural tube and the neural crest both give rise to neurons. Multipolar
neurons are the most common type. Bipolar neurons are found in the olfactory mucous mem- •
brane, in the ganglia of the vestibulocochlear nerve, and in the retina.

6

6. All of the following statements concerning myelin are correct EXCEPT
(A) it is produced by the microglia
(B) it is produced by Schwann cells
(C) it is produced by oligodendrocytes
(0) myelinating cells of the PNS myelinate only one internode
(E) myelinating cells of the CNS myelinate several internodes of different axons

6-A. Myelin is produced by Schwann cells in the peripheral nervous system (PNS) and by oligodendrocytes in the central nervous system (eNS). Schwann cells myelinnte only one internode; oligodendrocytes myelinat.e several internodes of different axons (up to 30). Microglial cells are the scavenger cells of the eNS; they do not produce myelin.

7

7. All of the following statements concerning Schwann cells are correct EXCEPT
(A) they play an important role in peripheral
(B) nerve regeneration (ll) they are derived from the neural tube
(C) they may give rise to tumors ofperipheral nerves
(D) one Schwann cell myelinates one inter¬node of an axon
(E) they are neurolemma! cells

7-B. Schwann cells (neurolemmal cells) play an important role in peripheral nerve regeneration. They are derived from the neural~ They-may give rise to benign tumors called schwannomas.
Schwann cells are the myelin-forming cells of the peripheral nervous system (PNS); they myelinate only one internode of an axon.

8

8. All of the following statements concerning wallerian degeneration are correct EXCEPT
(A) it occurs in the CNS
(8) it occurs in the PNS
(C) it is a retrograde degeneration
(D) itis characterized by the disappearance of axons and myelin sheaths
(E) it is characterized by the proliferation of Schwann cells

8-C. Wallerian degeneration is an anterograde degeneration of nerve fibers, characterized by
the disappearance ofaxons and myelin and by Schwann cell proliferation.

9

9. All of the following statements concerning sensory receptors are correct EXCEPT
(A) pain and thermal receptors utilize group Ib fibers
(B) Meissner corpuscles are found only in the dermal papillae of glabrous skin
(C) Merkel tactile disks mediate the sensa¬tion oflight touch
(0) pacinian corpuscles are acceleration de¬tectors that respond to vibration sensa¬tion •
(E) annulospiral endings project centrally via the dorsal column-medial lemniscus path¬way

9-A. Pain and thermal receptors utilize group A delta (fast pain) and C (slow pain) fibers. Pain
and thermal sensation are mediated via the lateral spinothalamic tract.

10

The response options for items 10-14 are the same. You will be required to select one answer for each item in the set.
(A) Astrocytes
(B) Oligodendrocytes
(C) Microglial cells
(D) Schwann cells
(E) Tanycytes

Match each of the following descriptions with the corresponding type of nerve cell.

10. Are a variety of ependymal cell found in the wall of the third ventricle

10-E. Tanycytes are a variety of ependymal cell found in the wall of the third ventricle. The
processes of these cells extend from the lumen of the third ventricle to the capillaries of the hy·
pophyseal portal system and also to the neurosecretory neurons of the arcuate nucleus.

11

The response options for items 10-14 are the same. You will be required to select one answer for each item in the set.
(A) Astrocytes
(B) Oligodendrocytes
(C) Microglial cells
(D) Schwann cells
(E) Tanycytes

Match each of the following descriptions with the corresponding type of nerve cell.

11. Arise from monocyte

ll-C. Microglial cells, the scavenger cells of the eNS, arise from monocytes and enter the CNS
via abnormal blood vessels.

12

The response options for items 10-14 are the same. You will be required to select one answer for each item in the set.
(A) Astrocytes
(B) Oligodendrocytes
(C) Microglial cells
(D) Schwann cells
(E) Tanycytes

Match each of the following descriptions with the corresponding type of nerve cell.

12. Are neural crest derivatives

12-D. Schwann cells are derived from the neural crest; they myelinate the axons of the PNS.

13

The response options for items 10-14 are the same. You will be required to select one answer for each item in the set.
(A) Astrocytes
(B) Oligodendrocytes
(C) Microglial cells
(D) Schwann cells
(E) Tanycytes

Match each of the following descriptions with the corresponding type of nerve cell.

13. Contain glial filaments and glycogen granules

13-A. Astrocytes are characterized by the presence of glial filamel.ts and glycogen; glial fila·
ments contain glial fibrillary acidic protein (GFAP), a marker for astrocytes.

14

The response options for items 10-14 are the same. You will be required to select one answer for each item in the set.
(A) Astrocytes
(B) Oligodendrocytes
(C) Microglial cells
(D) Schwann cells
(E) Tanycytes

Match each of the following descriptions with the corresponding type of nerve cell.

14. Are perineuronal satellite cells in the cen¬tral nervous system (CNS)

14-B. Oligodendrocytes are perineuronal satellite cells; they myelinate the axons of the central
nervous system (eNS).