Question 1

Which of the following best describes the role of voltage-gated calcium ion channels at a cholinergic synapse?

Accepted Answer

They facilitate the exocytosis of acetylcholine by allowing calcium ions to enter the presynaptic terminal.

Question 2

If a drug blocks acetylcholinesterase (AChE) activity at a synapse, what is the most likely effect on synaptic transmission?

Accepted Answer

Acetylcholine will accumulate in the synaptic cleft, prolonging its effect on the postsynaptic membrane.

Question 3

Which of the following is TRUE regarding synaptic delay?

Accepted Answer

It is the time between the arrival of an action potential at the presynaptic membrane and its effect on the postsynaptic membrane.

Question 4

A patient is given a medication that increases nitric oxide (NO) production in blood vessels. What physiological effect would you expect?

Accepted Answer

Vasodilation and decreased cardiac oxygen consumption.

Question 5

Which of the following best explains synaptic fatigue?

Accepted Answer

It results from the inability of the presynaptic neuron to synthesize and transport enough neurotransmitter during intense stimulation.

Question 6

Which of the following neurotransmitters is most widely used at neuromuscular junctions involving skeletal muscle fibers?

Accepted Answer

Acetylcholine

Question 7

Which of the following statements about neuromodulators is CORRECT?

Accepted Answer

They alter the rate of neurotransmitter release or change the postsynaptic cell's response, often producing longer-term effects.

Question 8

Which mechanism of action is used by lipid-soluble gases such as nitric oxide (NO) and carbon monoxide (CO) in neurotransmission?

Accepted Answer

Indirect effect through intracellular enzymes without the need for membrane receptors.

Question 9

Which of the following best describes the fate of acetylcholine (ACh) after it is released into the synaptic cleft?

Accepted Answer

It binds to receptors, then is broken down by acetylcholinesterase into acetate and choline.

Question 10

A neural pathway in the CNS consists of three neurons, while another consists of five neurons. Assuming all neurons are identical, which pathway will transmit impulses more rapidly and why?

Accepted Answer

The three-neuron pathway, because fewer synapses result in less cumulative synaptic delay.

Question 11

Which of the following is a correct multi-step sequence of events at a cholinergic synapse?

Accepted Answer

Action potential arrives at presynaptic terminal → voltage-gated calcium channels open → calcium ions enter → exocytosis of ACh → ACh binds to postsynaptic receptors → postsynaptic depolarization.

Question 12

Which of the following best describes the difference between neurotransmitters and neuromodulators?

Accepted Answer

Neurotransmitters directly affect postsynaptic membrane potentials, while neuromodulators alter the rate of neurotransmitter release or the postsynaptic cell's response.

Question 13

Which of the following is an example of an excitatory neurotransmitter and its effect?

Accepted Answer

Acetylcholine, which depolarizes the postsynaptic membrane and promotes action potential initiation.

Question 14

Which of the following equations correctly represents the hydrolysis of acetylcholine by acetylcholinesterase?

Accepted Answer

$\mathrm{Acetylcholine} + \mathrm{H}_2\mathrm{O} \xrightarrow{\mathrm{AChE}} \mathrm{Acetate} + \mathrm{Choline}$

Question 15

Which of the following mechanisms is NOT a way neurotransmitters and neuromodulators affect postsynaptic membrane potentials?

Accepted Answer

Direct effect by blocking voltage-gated sodium channels in the postsynaptic neuron.

Question 16

Which of the following statements about the structure of a chemical synapse is CORRECT?

Accepted Answer

The presynaptic terminal contains synaptic vesicles filled with neurotransmitters.

Question 17

Which of the following best explains why the fastest reflexes involve only one synapse?

Accepted Answer

Because each additional synapse increases the total synaptic delay, so fewer synapses result in a faster response.

Question 18

Which of the following is a correct statement about the mechanism of action for G-protein coupled receptors (GPCRs) in neurotransmission?

Accepted Answer

GPCRs activate second messengers, which then produce changes in membrane potential.

Nervous Tissue: Synapses, Neurotransmitters, and Neuromodulation

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