Guide Wilkes University Medication Classes +
150 Clinical Q&A | 2026/2027
1. During synaptic transmission, which of the following is the correct sequence of events at a
chemical synapse?
A. Action potential arrives → voltage-gated Ca²⁺ channels open → vesicle fusion →
neurotransmitter release into synaptic cleft → receptor binding
B. Neurotransmitter release → receptor binding → voltage-gated Ca²⁺ channels open → vesicle
fusion → action potential propagation
C. Voltage-gated Na⁺ channels open at the synapse → Ca²⁺ influx → neurotransmitter synthesis
→ vesicle docking → receptor activation
D. Receptor binding → G-protein activation → second messenger formation → Ca²⁺ influx →
vesicle fusion and neurotransmitter release
Correct Answer: A. Action potential arrives → voltage-gated Ca²⁺ channels open → vesicle
fusion → neurotransmitter release into synaptic cleft → receptor binding
Rationale: The correct sequence of chemical synaptic transmission begins with an action
potential reaching the presynaptic terminal, which opens voltage-gated calcium channels.
Calcium influx triggers synaptic vesicle fusion with the presynaptic membrane and
neurotransmitter release into the synaptic cleft, where it binds to postsynaptic receptors.
Options B, C, and D reverse the sequence or describe events out of order.
2. A nurse practitioner is explaining the all-or-nothing principle of action potentials. Which
statement accurately describes this principle?
,A. Action potentials vary in amplitude depending on stimulus intensity
B. Once the threshold potential (−55 mV) is reached, the action potential fires at full amplitude
regardless of further stimulus strength
C. Action potentials require continuous neurotransmitter release to be sustained along the axon
D. The refractory period allows graded potentials to summate and generate a larger action
potential
Correct Answer: B. Once the threshold potential (−55 mV) is reached, the action potential fires
at full amplitude regardless of further stimulus strength
Rationale: The all-or-nothing principle states that once membrane depolarization reaches
threshold (approximately −55 mV), the action potential is generated at full amplitude and
cannot be partially fired. Option A describes graded potentials, option C confuses action
potential propagation with synaptic transmission, and option D mischaracterizes the refractory
period.
3. A patient taking a serotonergic antidepressant reports improvement in mood, sleep, and
appetite. Which neurotransmitter system is most directly responsible for regulating all three of
these domains?
A. Dopamine
B. Norepinephrine
C. Gamma-aminobutyric acid (GABA)
D. Serotonin (5-hydroxytryptamine, 5-HT)
Correct Answer: D. Serotonin (5-hydroxytryptamine, 5-HT)
, Rationale: Serotonin (5-HT) is the primary neurotransmitter involved in the regulation of mood,
sleep, and appetite, which is why SSRIs and other serotonergic agents effectively address these
symptoms in depression and anxiety disorders. Dopamine regulates reward and motor function,
norepinephrine mediates arousal and stress responses, and GABA is the primary inhibitory
neurotransmitter.
4. Which brain region is the primary site of action for the therapeutic effects of selective
serotonin reuptake inhibitors (SSRIs)?
A. Substantia nigra
B. Raphe nuclei
C. Ventral tegmental area
D. Locus coeruleus
Correct Answer: B. Raphe nuclei
Rationale: The raphe nuclei are clusters of serotonin-producing neurons in the brainstem that
project widely throughout the brain. SSRIs increase serotonin availability at synapses originating
from the raphe nuclei. The substantia nigra contains dopaminergic neurons, the ventral
tegmental area is a major dopamine source, and the locus coeruleus is the primary source of
norepinephrine.
5. The mesolimbic dopamine pathway is best described as projecting from the _____ to the
_____.