TEST BANK For Clinical Neuroanatomy: A
Review with Questions and Explanations (2nd
Edition) by Richard S. Snell.
National Board–Style MCQs with 100%
Correct Answers and Explanations
,Topic 1: Organization of the Nervous
System and the Neurobiology of the
Neuron
1. The most excitable part of a neuron where an action potential is
normally initiated is the:
A. Dendrite
B. Cell body
C. Axon hillock
D. Initial segment of the axon
E. Axon terminal
Correct Answer: D
Explanation:
The initial segment of the axon has the highest density of voltage-gated sodium channels,
making it the site where action potentials normally originate.
2. Which of the following neurons is typically found in the posterior root
ganglion?
A. Multipolar
B. Bipolar
C. Unipolar
D. Golgi type II
E. Pyramidal
Correct Answer: C
Explanation:
Posterior root ganglion neurons are unipolar (pseudounipolar), with a single process that
divides into peripheral and central branches.
,3. Which cell type forms myelin in the peripheral nervous system?
A. Astrocyte
B. Oligodendrocyte
C. Schwann cell
D. Microglia
E. Ependymal cell
Correct Answer: C
Explanation:
Schwann cells myelinate axons in the peripheral nervous system, whereas
oligodendrocytes myelinate CNS axons.
4. The major dense line seen in electron micrographs of myelinated fibers
represents:
A. Axolemma
B. Fused outer plasma membranes
C. Fused inner plasma membranes
D. Basement membrane
E. Nodes of Ranvier
Correct Answer: C
Explanation:
The major dense line is formed by the fusion of the inner protein layers of the Schwann cell
plasma membrane during myelination.
5. Which structure is absent from the axoplasm of a normal axon?
A. Microtubules
B. Mitochondria
C. Neurofibrils
D. Nissl substance
E. Vesicles
Correct Answer: D
Explanation:
, Nissl substance (rough endoplasmic reticulum) is present in the cell body and dendrites but
absent in axons.
6. Which ion is primarily responsible for depolarization during an action
potential?
A. Potassium
B. Calcium
C. Chloride
D. Sodium
E. Magnesium
Correct Answer: D
Explanation:
Depolarization occurs due to rapid influx of sodium ions (Na⁺) through voltage-gated
sodium channels.
7. The resting membrane potential of a neuron is approximately:
A. +40 mV
B. 0 mV
C. −40 mV
D. −70 to −80 mV
E. −120 mV
Correct Answer: D
Explanation:
The resting membrane potential is approximately −70 to −80 mV, with the interior negative
relative to the exterior.
8. Saltatory conduction occurs in:
A. Nonmyelinated fibers
B. Small-diameter axons
C. Dendrites
D. Myelinated axons
Review with Questions and Explanations (2nd
Edition) by Richard S. Snell.
National Board–Style MCQs with 100%
Correct Answers and Explanations
,Topic 1: Organization of the Nervous
System and the Neurobiology of the
Neuron
1. The most excitable part of a neuron where an action potential is
normally initiated is the:
A. Dendrite
B. Cell body
C. Axon hillock
D. Initial segment of the axon
E. Axon terminal
Correct Answer: D
Explanation:
The initial segment of the axon has the highest density of voltage-gated sodium channels,
making it the site where action potentials normally originate.
2. Which of the following neurons is typically found in the posterior root
ganglion?
A. Multipolar
B. Bipolar
C. Unipolar
D. Golgi type II
E. Pyramidal
Correct Answer: C
Explanation:
Posterior root ganglion neurons are unipolar (pseudounipolar), with a single process that
divides into peripheral and central branches.
,3. Which cell type forms myelin in the peripheral nervous system?
A. Astrocyte
B. Oligodendrocyte
C. Schwann cell
D. Microglia
E. Ependymal cell
Correct Answer: C
Explanation:
Schwann cells myelinate axons in the peripheral nervous system, whereas
oligodendrocytes myelinate CNS axons.
4. The major dense line seen in electron micrographs of myelinated fibers
represents:
A. Axolemma
B. Fused outer plasma membranes
C. Fused inner plasma membranes
D. Basement membrane
E. Nodes of Ranvier
Correct Answer: C
Explanation:
The major dense line is formed by the fusion of the inner protein layers of the Schwann cell
plasma membrane during myelination.
5. Which structure is absent from the axoplasm of a normal axon?
A. Microtubules
B. Mitochondria
C. Neurofibrils
D. Nissl substance
E. Vesicles
Correct Answer: D
Explanation:
, Nissl substance (rough endoplasmic reticulum) is present in the cell body and dendrites but
absent in axons.
6. Which ion is primarily responsible for depolarization during an action
potential?
A. Potassium
B. Calcium
C. Chloride
D. Sodium
E. Magnesium
Correct Answer: D
Explanation:
Depolarization occurs due to rapid influx of sodium ions (Na⁺) through voltage-gated
sodium channels.
7. The resting membrane potential of a neuron is approximately:
A. +40 mV
B. 0 mV
C. −40 mV
D. −70 to −80 mV
E. −120 mV
Correct Answer: D
Explanation:
The resting membrane potential is approximately −70 to −80 mV, with the interior negative
relative to the exterior.
8. Saltatory conduction occurs in:
A. Nonmyelinated fibers
B. Small-diameter axons
C. Dendrites
D. Myelinated axons
