Question 1

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

Accepted Answer

Electrical synapses transmit signals through gap junctions, allowing direct ion flow, while chemical synapses use neurotransmitters to carry information across the synaptic cleft.

Question 2

Which of the following events occurs first during neurotransmitter release at a chemical synapse?

Accepted Answer

Voltage-gated Ca$$^{2+}$$ channels open in the presynaptic membrane.

Question 3

A postsynaptic potential that makes the neuron more likely to fire an action potential is called:

Accepted Answer

Excitatory postsynaptic potential (EPSP)

Question 4

Which of the following mechanisms is NOT a way to terminate neurotransmitter signaling at a synapse?

Accepted Answer

Continuous stimulation of postsynaptic receptors

Question 5

Which neurotransmitter is most directly associated with the regulation of mood and is often targeted by antidepressant medications?

Accepted Answer

Serotonin

Question 6

A patient is exposed to sarin gas, which inhibits acetylcholinesterase. What is the most immediate effect on synaptic transmission?

Accepted Answer

Increased acetylcholine in the synaptic cleft, causing continuous stimulation of muscles

Question 7

Which of the following best explains why summation of postsynaptic potentials is necessary for action potential generation?

Accepted Answer

A single EPSP is usually too small to reach the threshold for an action potential.

Question 8

Which of the following is a correct example of spatial summation?

Accepted Answer

EPSPs from different synapses on the same postsynaptic neuron combine to reach threshold

Question 9

Which of the following neurotransmitters is classified as a biogenic amine?

Accepted Answer

Dopamine

Question 10

A drug that blocks the reuptake of dopamine in the synaptic cleft would most likely:

Accepted Answer

Increase dopamine signaling by prolonging its action in the synaptic cleft

Question 11

Which of the following best describes the role of endorphins in the nervous system?

Accepted Answer

They bind to opioid receptors and reduce the perception of pain.

Question 12

Which of the following is a likely effect of a drug that acts as a GABA agonist in the brain?

Accepted Answer

Decreased neuronal excitability and increased inhibition

Question 13

Which equation best represents the Nernst equation for calculating the equilibrium potential for an ion?

Accepted Answer

$$E = \frac{RT}{zF} \ln \left( \frac{[	ext{ion}]_{	ext{outside}}}{[	ext{ion}]_{	ext{inside}}} ight)$$

Question 14

Which of the following scenarios best illustrates temporal summation?

Accepted Answer

Multiple EPSPs occur in rapid succession at the same synapse, adding together

Question 15

Which of the following is a direct effect of an inhibitory postsynaptic potential (IPSP)?

Accepted Answer

Hyperpolarization of the postsynaptic membrane

Question 16

Which of the following best explains why SSRIs (selective serotonin reuptake inhibitors) are effective in treating depression?

Accepted Answer

They block the reuptake of serotonin, increasing its availability in the synaptic cleft.

Question 17

Which of the following is a neuropeptide involved in pain perception?

Accepted Answer

Substance P

Question 18

Which of the following is a likely effect of a drug that inhibits the enzyme acetylcholinesterase?

Accepted Answer

Prolonged stimulation of acetylcholine receptors

Question 19

Which of the following best describes the function of gap junctions in electrical synapses?

Accepted Answer

They allow direct passage of ions between neurons, enabling rapid signal transmission.

Question 20

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

Accepted Answer

Action potential arrival → Ca$$^{2+}$$ influx → Vesicle fusion → Neurotransmitter release

Neurobiology: Synaptic Transmission and Neurotransmitters

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