BIOL 322 Neuroscience: Comprehensive Final
Examination 2026 | 200 Advanced Multiple-Choice
Questions with Verified Answers, Detailed
Rationales & Clinical Correlations | Complete Study
Guide
SECTION 1: CELLULAR AND MOLECULAR NEUROSCIENCE (Questions 1–50)
1. A researcher records from a neuron and finds the resting membrane potential is −70 mV.
Which ion contributes MOST to setting this potential?
A. Sodium (Na⁺)
B. Potassium (K⁺)
C. Calcium (Ca²⁺)
D. Chloride (Cl⁻)
Correct Answer: B
Rationale: The resting membrane potential is dominated by K⁺ permeability at rest because of
open leak K⁺ channels and the steep K⁺ concentration gradient. Na⁺ has a large driving force but
low resting permeability. Cl⁻ distributes passively and contributes little at typical resting
potentials.
2. During the rising phase of the action potential, which conductance change is responsible?
A. Increased K⁺ conductance
B. Increased Na⁺ conductance
C. Increased Cl⁻ conductance
D. Decreased Ca²⁺ conductance
Correct Answer: B
1
,Rationale: Depolarization opens voltage-gated Na⁺ channels, and Na⁺ influx drives the
membrane toward E_Na (+60 mV). K⁺ conductance increases later, producing repolarization.
3. Tetrodotoxin (TTX) blocks which component of the action potential?
A. Repolarization
B. The afterhyperpolarization
C. The rising phase
D. The refractory period only
Correct Answer: C
Rationale: TTX is a selective blocker of voltage-gated Na⁺ channels. Blocking these channels
eliminates the rapid depolarizing (rising) phase without directly affecting K⁺-mediated
repolarization.
4. Which property of the action potential ensures unidirectional propagation along an axon?
A. The absolute refractory period
B. The relative refractory period
C. Saltatory conduction
D. Myelination
Correct Answer: A
Rationale: During the absolute refractory period, Na⁺ channels are inactivated, so the
membrane behind the advancing action potential cannot be re-excited. This enforces one-way
conduction.
5. In myelinated axons, conduction velocity increases primarily because:
A. The axon diameter increases
B. Myelin increases membrane capacitance
C. Myelin decreases membrane capacitance and increases resistance
D. Na⁺ channels are removed from nodes
Correct Answer: C
2
,Rationale: Myelin reduces capacitance and increases membrane resistance, allowing current to
spread farther and faster between nodes (saltatory conduction). Nodes of Ranvier retain high
Na⁺ channel density.
6. A patient with multiple sclerosis experiences slowed conduction because:
A. Axons are severed
B. Myelin is destroyed, increasing capacitance and current leakage
C. Neurotransmitter release is blocked
D. Na⁺ channels are overexpressed
Correct Answer: B
Rationale: Demyelination increases membrane capacitance and decreases resistance, reducing
the length constant and slowing or blocking conduction. This produces the classic conduction
deficits of MS.
7. Which statement about graded potentials is CORRECT?
A. They are all-or-none
B. They decay with distance
C. They require voltage-gated Na⁺ channels
D. They propagate without decrement
Correct Answer: B
Rationale: Graded potentials are passive, decremental signals whose amplitude decreases with
distance. They can summate and do not require voltage-gated Na⁺ channels.
8. Temporal summation occurs when:
A. Multiple synapses fire simultaneously
B. One synapse fires repeatedly in rapid succession
C. Inhibitory inputs cancel excitation
D. Axon hillock threshold is lowered
Correct Answer: B
Rationale: Temporal summation refers to the addition of postsynaptic potentials generated at
the same synapse over a short time. Spatial summation involves multiple synapses.
3
, 9. Which neurotransmitter is primarily responsible for fast excitatory synaptic transmission in
the CNS?
A. GABA
B. Glycine
C. Glutamate
D. Dopamine
Correct Answer: C
Rationale: Glutamate is the major fast excitatory neurotransmitter, acting largely on AMPA and
NMDA receptors. GABA and glycine are inhibitory.
10. Long-term potentiation (LTP) in the hippocampus requires:
A. GABA_A receptor activation
B. NMDA receptor activation and Ca²⁺ influx
C. Glycine receptor activation
D. Dopamine D2 receptor blockade
Correct Answer: B
Rationale: LTP at CA1 synapses requires NMDA receptor activation, Ca²⁺ influx, and downstream
CaMKII signaling, leading to increased AMPA receptor insertion and synaptic strengthening.
11. Which glial cell is responsible for myelination in the peripheral nervous system?
A. Astrocyte
B. Oligodendrocyte
C. Schwann cell
D. Microglia
Correct Answer: C
Rationale: Schwann cells myelinate axons in the PNS. Oligodendrocytes myelinate CNS axons.
Astrocytes and microglia perform other support and immune functions.
4
Examination 2026 | 200 Advanced Multiple-Choice
Questions with Verified Answers, Detailed
Rationales & Clinical Correlations | Complete Study
Guide
SECTION 1: CELLULAR AND MOLECULAR NEUROSCIENCE (Questions 1–50)
1. A researcher records from a neuron and finds the resting membrane potential is −70 mV.
Which ion contributes MOST to setting this potential?
A. Sodium (Na⁺)
B. Potassium (K⁺)
C. Calcium (Ca²⁺)
D. Chloride (Cl⁻)
Correct Answer: B
Rationale: The resting membrane potential is dominated by K⁺ permeability at rest because of
open leak K⁺ channels and the steep K⁺ concentration gradient. Na⁺ has a large driving force but
low resting permeability. Cl⁻ distributes passively and contributes little at typical resting
potentials.
2. During the rising phase of the action potential, which conductance change is responsible?
A. Increased K⁺ conductance
B. Increased Na⁺ conductance
C. Increased Cl⁻ conductance
D. Decreased Ca²⁺ conductance
Correct Answer: B
1
,Rationale: Depolarization opens voltage-gated Na⁺ channels, and Na⁺ influx drives the
membrane toward E_Na (+60 mV). K⁺ conductance increases later, producing repolarization.
3. Tetrodotoxin (TTX) blocks which component of the action potential?
A. Repolarization
B. The afterhyperpolarization
C. The rising phase
D. The refractory period only
Correct Answer: C
Rationale: TTX is a selective blocker of voltage-gated Na⁺ channels. Blocking these channels
eliminates the rapid depolarizing (rising) phase without directly affecting K⁺-mediated
repolarization.
4. Which property of the action potential ensures unidirectional propagation along an axon?
A. The absolute refractory period
B. The relative refractory period
C. Saltatory conduction
D. Myelination
Correct Answer: A
Rationale: During the absolute refractory period, Na⁺ channels are inactivated, so the
membrane behind the advancing action potential cannot be re-excited. This enforces one-way
conduction.
5. In myelinated axons, conduction velocity increases primarily because:
A. The axon diameter increases
B. Myelin increases membrane capacitance
C. Myelin decreases membrane capacitance and increases resistance
D. Na⁺ channels are removed from nodes
Correct Answer: C
2
,Rationale: Myelin reduces capacitance and increases membrane resistance, allowing current to
spread farther and faster between nodes (saltatory conduction). Nodes of Ranvier retain high
Na⁺ channel density.
6. A patient with multiple sclerosis experiences slowed conduction because:
A. Axons are severed
B. Myelin is destroyed, increasing capacitance and current leakage
C. Neurotransmitter release is blocked
D. Na⁺ channels are overexpressed
Correct Answer: B
Rationale: Demyelination increases membrane capacitance and decreases resistance, reducing
the length constant and slowing or blocking conduction. This produces the classic conduction
deficits of MS.
7. Which statement about graded potentials is CORRECT?
A. They are all-or-none
B. They decay with distance
C. They require voltage-gated Na⁺ channels
D. They propagate without decrement
Correct Answer: B
Rationale: Graded potentials are passive, decremental signals whose amplitude decreases with
distance. They can summate and do not require voltage-gated Na⁺ channels.
8. Temporal summation occurs when:
A. Multiple synapses fire simultaneously
B. One synapse fires repeatedly in rapid succession
C. Inhibitory inputs cancel excitation
D. Axon hillock threshold is lowered
Correct Answer: B
Rationale: Temporal summation refers to the addition of postsynaptic potentials generated at
the same synapse over a short time. Spatial summation involves multiple synapses.
3
, 9. Which neurotransmitter is primarily responsible for fast excitatory synaptic transmission in
the CNS?
A. GABA
B. Glycine
C. Glutamate
D. Dopamine
Correct Answer: C
Rationale: Glutamate is the major fast excitatory neurotransmitter, acting largely on AMPA and
NMDA receptors. GABA and glycine are inhibitory.
10. Long-term potentiation (LTP) in the hippocampus requires:
A. GABA_A receptor activation
B. NMDA receptor activation and Ca²⁺ influx
C. Glycine receptor activation
D. Dopamine D2 receptor blockade
Correct Answer: B
Rationale: LTP at CA1 synapses requires NMDA receptor activation, Ca²⁺ influx, and downstream
CaMKII signaling, leading to increased AMPA receptor insertion and synaptic strengthening.
11. Which glial cell is responsible for myelination in the peripheral nervous system?
A. Astrocyte
B. Oligodendrocyte
C. Schwann cell
D. Microglia
Correct Answer: C
Rationale: Schwann cells myelinate axons in the PNS. Oligodendrocytes myelinate CNS axons.
Astrocytes and microglia perform other support and immune functions.
4
