Neuroscience Purves 6th Ed. Chapters 1-34 Actual Exam 2026/2027 –
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Section 1: Cellular Neuroscience, Neuroanatomy & Signaling (25
questions)
Q1: A patient presents with progressive weakness and sensory loss in the distal
extremities. Nerve biopsy reveals onion bulb formations and segmental demyelination.
Which glial cell type is primarily affected in this peripheral neuropathy?
A. Oligodendrocytes, which myelinate CNS axons in multiple segments
B. Astrocytes, which regulate the blood-brain barrier and ion homeostasis
C. Schwann cells, which myelinate single internodes in the PNS [CORRECT]
D. Microglia, which function as resident immune cells of the CNS
Correct Answer: C
Rationale: Schwann cells are the myelinating glia of the peripheral nervous system, each
wrapping a single internode around one axon. Onion bulb formations are
pathognomonic for recurrent demyelination and remyelination in peripheral
neuropathies such as Charcot-Marie-Tooth disease, as described in Purves
Neuroscience 6th Edition Chapter 1.
,Q2: During a neurosurgical procedure, a surgeon notes a prominent swelling at the base
of a cortical pyramidal neuron's axon where it emerges from the cell body. This structure
is critical for action potential initiation because:
A. It contains the highest density of K+ leak channels, establishing the resting
membrane potential
B. It is the site of highest Na+ channel density and lowest threshold for voltage-gated
channel activation [CORRECT]
C. It serves exclusively as the anchor point for microtubule-associated proteins during
axonal transport
D. It functions primarily as a reservoir for synaptic vesicles prior to anterograde
transport
Correct Answer: B
Rationale: The axon hillock contains the highest density of voltage-gated Na+ channels
in the neuron and has the lowest threshold for action potential initiation, serving as the
spike initiation zone where graded potentials are integrated and converted to all-or-none
signals, per Purves Chapter 2.
Q3: A researcher uses Golgi's silver impregnation method to visualize neurons in
cortical tissue. Compared to Nissl staining, this technique reveals:
A. The distribution of all cell bodies in a given tissue section with 100% sampling
efficiency
B. Only a random subset of neurons in their entirety, including dendritic arborization and
axonal projections [CORRECT]
C. Myelinated axon tracts with high specificity for oligodendrocyte processes
,D. Synaptic vesicle populations and presynaptic terminal morphology exclusively
Correct Answer: B
Rationale: Golgi's method impregnates a random 1-5% of neurons completely, revealing
dendritic trees, spines, and initial axonal segments, while Nissl stains all cell bodies; this
stochastic staining was crucial for Cajal's neuron doctrine, as detailed in Purves Chapter
1.
Q4: In a molecular neuroscience experiment, a researcher isolates mRNA from neurons
and observes that the mature transcript is considerably shorter than the corresponding
genomic DNA sequence. This difference is best explained by:
A. Post-translational modification of the protein product shortening the polypeptide
chain
B. Alternative splicing removing introns and joining exons to produce the mature mRNA
[CORRECT]
C. DNA methylation of promoter regions reducing transcriptional output
D. Ribosomal frameshifting during translation altering the reading frame
Correct Answer: B
Rationale: Eukaryotic genes contain introns (non-coding intervening sequences) and
exons (coding sequences); during transcription and RNA processing, introns are spliced
out and exons are joined to produce mature mRNA, a fundamental mechanism for
proteomic diversity in neurons, per Purves Chapter 2.
, Q5: A 45-year-old patient develops acute ascending paralysis following a
gastrointestinal infection. Electrophysiological studies show slowed nerve conduction
velocities. The autoimmune destruction of which structure is most likely responsible?
A. Astrocytic end-feet surrounding CNS capillaries
B. Myelin sheaths produced by Schwann cells in peripheral nerves [CORRECT]
C. Microglial cell bodies within the spinal cord gray matter
D. Oligodendrocyte processes wrapping CNS axons
Correct Answer: B
Rationale: Guillain-Barré syndrome is an acute inflammatory demyelinating
polyneuropathy characterized by autoimmune attack on peripheral nerve myelin
produced by Schwann cells, resulting in slowed conduction velocities and ascending
weakness, as described in Purves Chapters 1 and 27.
Q6: During patch-clamp recording of a resting neuron, the membrane potential
measures -70 mV. If the extracellular K+ concentration is increased from 5 mM to 10
mM, the membrane potential will:
A. Hyperpolarize to approximately -85 mV due to increased K+ efflux
B. Depolarize toward a less negative value because the K+ equilibrium potential
becomes less negative [CORRECT]
C. Remain unchanged because the Na+/K+ ATPase maintains a fixed membrane
potential
Comprehensive Test Bank with Detailed Rationales | 100% Verified | Pass
Guaranteed – A+ Graded
Section 1: Cellular Neuroscience, Neuroanatomy & Signaling (25
questions)
Q1: A patient presents with progressive weakness and sensory loss in the distal
extremities. Nerve biopsy reveals onion bulb formations and segmental demyelination.
Which glial cell type is primarily affected in this peripheral neuropathy?
A. Oligodendrocytes, which myelinate CNS axons in multiple segments
B. Astrocytes, which regulate the blood-brain barrier and ion homeostasis
C. Schwann cells, which myelinate single internodes in the PNS [CORRECT]
D. Microglia, which function as resident immune cells of the CNS
Correct Answer: C
Rationale: Schwann cells are the myelinating glia of the peripheral nervous system, each
wrapping a single internode around one axon. Onion bulb formations are
pathognomonic for recurrent demyelination and remyelination in peripheral
neuropathies such as Charcot-Marie-Tooth disease, as described in Purves
Neuroscience 6th Edition Chapter 1.
,Q2: During a neurosurgical procedure, a surgeon notes a prominent swelling at the base
of a cortical pyramidal neuron's axon where it emerges from the cell body. This structure
is critical for action potential initiation because:
A. It contains the highest density of K+ leak channels, establishing the resting
membrane potential
B. It is the site of highest Na+ channel density and lowest threshold for voltage-gated
channel activation [CORRECT]
C. It serves exclusively as the anchor point for microtubule-associated proteins during
axonal transport
D. It functions primarily as a reservoir for synaptic vesicles prior to anterograde
transport
Correct Answer: B
Rationale: The axon hillock contains the highest density of voltage-gated Na+ channels
in the neuron and has the lowest threshold for action potential initiation, serving as the
spike initiation zone where graded potentials are integrated and converted to all-or-none
signals, per Purves Chapter 2.
Q3: A researcher uses Golgi's silver impregnation method to visualize neurons in
cortical tissue. Compared to Nissl staining, this technique reveals:
A. The distribution of all cell bodies in a given tissue section with 100% sampling
efficiency
B. Only a random subset of neurons in their entirety, including dendritic arborization and
axonal projections [CORRECT]
C. Myelinated axon tracts with high specificity for oligodendrocyte processes
,D. Synaptic vesicle populations and presynaptic terminal morphology exclusively
Correct Answer: B
Rationale: Golgi's method impregnates a random 1-5% of neurons completely, revealing
dendritic trees, spines, and initial axonal segments, while Nissl stains all cell bodies; this
stochastic staining was crucial for Cajal's neuron doctrine, as detailed in Purves Chapter
1.
Q4: In a molecular neuroscience experiment, a researcher isolates mRNA from neurons
and observes that the mature transcript is considerably shorter than the corresponding
genomic DNA sequence. This difference is best explained by:
A. Post-translational modification of the protein product shortening the polypeptide
chain
B. Alternative splicing removing introns and joining exons to produce the mature mRNA
[CORRECT]
C. DNA methylation of promoter regions reducing transcriptional output
D. Ribosomal frameshifting during translation altering the reading frame
Correct Answer: B
Rationale: Eukaryotic genes contain introns (non-coding intervening sequences) and
exons (coding sequences); during transcription and RNA processing, introns are spliced
out and exons are joined to produce mature mRNA, a fundamental mechanism for
proteomic diversity in neurons, per Purves Chapter 2.
, Q5: A 45-year-old patient develops acute ascending paralysis following a
gastrointestinal infection. Electrophysiological studies show slowed nerve conduction
velocities. The autoimmune destruction of which structure is most likely responsible?
A. Astrocytic end-feet surrounding CNS capillaries
B. Myelin sheaths produced by Schwann cells in peripheral nerves [CORRECT]
C. Microglial cell bodies within the spinal cord gray matter
D. Oligodendrocyte processes wrapping CNS axons
Correct Answer: B
Rationale: Guillain-Barré syndrome is an acute inflammatory demyelinating
polyneuropathy characterized by autoimmune attack on peripheral nerve myelin
produced by Schwann cells, resulting in slowed conduction velocities and ascending
weakness, as described in Purves Chapters 1 and 27.
Q6: During patch-clamp recording of a resting neuron, the membrane potential
measures -70 mV. If the extracellular K+ concentration is increased from 5 mM to 10
mM, the membrane potential will:
A. Hyperpolarize to approximately -85 mV due to increased K+ efflux
B. Depolarize toward a less negative value because the K+ equilibrium potential
becomes less negative [CORRECT]
C. Remain unchanged because the Na+/K+ ATPase maintains a fixed membrane
potential
