Question 1

Which of the following best describes the main difference between electrical and chemical synapses in the nervous system?

Accepted Answer

Electrical synapses transmit signals via direct ion flow through gap junctions, while chemical synapses use neurotransmitters to communicate across a synaptic cleft.

Question 2

A gymnast suffers an injury and is given morphine for pain relief. Which mechanism best explains how morphine reduces her pain sensation?

Accepted Answer

Morphine binds to opioid receptors, mimicking endorphins and enkephalins, which inhibit neurotransmitter release in pain pathways.

Question 3

During synaptic transmission at a chemical synapse, which ion's influx into the presynaptic terminal is directly responsible for triggering neurotransmitter release?

Accepted Answer

Calcium ($Ca^{2+}$)

Question 4

Which of the following best explains why the effect of a neurotransmitter at a chemical synapse is usually unidirectional?

Accepted Answer

Neurotransmitter vesicles are only present in the presynaptic terminal, and receptors are only on the postsynaptic membrane.

Question 5

A postsynaptic neuron receives both excitatory and inhibitory inputs. If the sum of the excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic potentials (IPSPs) brings the membrane potential to threshold, what will occur?

Accepted Answer

The postsynaptic neuron will fire an action potential.

Question 6

Which of the following equations correctly represents the Nernst equation for calculating the equilibrium potential ($E_{ion}$) for a given ion?

Accepted Answer

$E_{ion} = \frac{RT}{zF} \ln \left( \frac{[ion]_{out}}{[ion]_{in}} \right)$

Question 7

A patient is given a drug that blocks the reuptake of serotonin in the brain. What is the most likely effect of this drug on synaptic transmission?

Accepted Answer

It will increase the duration and intensity of serotonin's action on the postsynaptic neuron.

Question 8

Which of the following best describes spatial summation in neural integration?

Accepted Answer

Simultaneous stimulation of a postsynaptic neuron by multiple presynaptic neurons at different locations.

Question 9

Which neurotransmitter is synthesized from choline and acetyl-CoA, and is rapidly degraded in the synaptic cleft by acetylcholinesterase?

Accepted Answer

Acetylcholine

Question 10

A neuron releases GABA at its synapse. What is the most likely effect on the postsynaptic cell?

Accepted Answer

Hyperpolarization due to chloride influx

Question 11

Which of the following best describes the process of presynaptic facilitation?

Accepted Answer

A presynaptic neuron increases neurotransmitter release from another presynaptic neuron, enhancing the postsynaptic response.

Question 12

Which of the following is a biogenic amine neurotransmitter that is associated with mood regulation and is targeted by many antidepressant drugs?

Accepted Answer

Serotonin

Question 13

Which of the following best explains why the postsynaptic response at a chemical synapse is terminated rapidly after neurotransmitter release?

Accepted Answer

Neurotransmitter molecules are quickly degraded, reuptaken, or diffuse away from the synaptic cleft.

Question 14

Which of the following neurotransmitters is the primary excitatory neurotransmitter in the central nervous system and acts on both AMPA and NMDA receptors?

Accepted Answer

Glutamate

Question 15

A postsynaptic neuron receives two EPSPs from different presynaptic neurons at the same time, and one IPSP from a third neuron. If the net effect is depolarization but not enough to reach threshold, what will happen?

Accepted Answer

The postsynaptic neuron will remain below threshold and not fire an action potential.

Question 16

Which of the following is a correct sequence of events for neurotransmitter release at a chemical synapse?

Accepted Answer

Action potential arrives at axon terminal → voltage-gated calcium channels open → calcium influx → vesicle fusion and neurotransmitter release

Question 17

Which of the following best describes the role of acetylcholinesterase at the neuromuscular junction?

Accepted Answer

It degrades acetylcholine in the synaptic cleft, terminating the signal.

Question 18

Which of the following is a unique feature of electrical synapses compared to chemical synapses?

Accepted Answer

They allow bidirectional flow of ions through gap junctions, enabling rapid communication.

Question 19

Which of the following best describes the function of autoreceptors on the presynaptic neuron?

Accepted Answer

They detect neurotransmitter released by the same neuron and inhibit further release.

Synaptic Transmission: Electrical and Chemical Synapses in the Nervous System

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