Question 1

Which of the following best describes the function of the enteric nervous system (ENS)?

Accepted Answer

It initiates and coordinates visceral reflexes locally within the digestive tract, often without instructions from the CNS.

Question 2

A patient suffers an injury that damages the myelin sheath in the CNS. Which neuroglia is most likely affected, and what is the consequence for nerve impulse transmission?

Accepted Answer

Oligodendrocytes; decreased speed of action potential propagation in the CNS.

Question 3

Which structural type of neuron is most commonly found in the peripheral nervous system as sensory neurons?

Accepted Answer

Unipolar (pseudounipolar) neurons

Question 4

During the generation of an action potential, what happens when the membrane potential reaches +30 mV?

Accepted Answer

Voltage-gated sodium channels inactivate and voltage-gated potassium channels open, allowing K$$^+ to $$leave the cell.

Question 5

Which equation best represents the action of the sodium-potassium exchange pump in maintaining the resting membrane potential?

Accepted Answer

For every 3 Na$$^+$$ ions ejected, 2 K$$^+$$ ions are brought in: $$3\ 	ext{Na}^+_{	ext{out}} ightarrow 2\ 	ext{K}^+_{	ext{in}}$$

Question 6

A neuron receives two simultaneous excitatory stimuli at different locations on its dendrites. What is this process called, and what is the likely result?

Accepted Answer

Spatial summation; the effects of the stimuli are combined, increasing the likelihood of reaching threshold.

Question 7

Which of the following is TRUE regarding the propagation of action potentials in myelinated axons?

Accepted Answer

Saltatory propagation occurs, where the action potential jumps from node to node, increasing speed.

Question 8

A neuron is exposed to a chemical that opens potassium ion channels. What is the effect on the membrane potential?

Accepted Answer

Hyperpolarization occurs as positive ions leave the cell, increasing negativity.

Question 9

Which of the following best explains why Type A fibers transmit information more rapidly than Type C fibers?

Accepted Answer

Type A fibers are myelinated and have large diameters, resulting in low resistance and fast propagation.

Question 10

Which neurotransmitter is released at all neuromuscular junctions involving skeletal muscle fibers and is broken down by acetylcholinesterase?

Accepted Answer

Acetylcholine

Question 11

A neuron is inhibited from producing an action potential because it receives many IPSPs. What is the effect on the threshold for action potential generation?

Accepted Answer

The threshold is increased, making it harder to trigger an action potential.

Question 12

Which of the following is a function of astrocytes in the CNS?

Accepted Answer

Maintain the blood-brain barrier and repair damaged nervous tissue

Question 13

Which type of ion channel opens in response to a neurotransmitter binding to its receptor on the postsynaptic membrane?

Accepted Answer

Chemically gated (ligand-gated) ion channel

Question 14

Which of the following best describes the 'all-or-none' principle of action potentials?

Accepted Answer

Any stimulus that reaches threshold will trigger an action potential of the same size.

Question 15

Which of the following is a direct effect of neurotransmitters on postsynaptic membranes?

Accepted Answer

Opening or closing chemically gated ion channels, such as ACh, glutamate, or aspartate

Question 16

A patient presents with symptoms of synaptic fatigue after intense neural activity. What is the most likely cause?

Accepted Answer

Inability to recycle neurotransmitter fast enough to meet demands, leading to weakened synaptic response

Question 17

Which of the following best describes the effect of neuromodulators?

Accepted Answer

They alter the rate of neurotransmitter release or the response of the postsynaptic cell, with effects that are long-term and slow to appear.

Question 18

Which of the following statements about graded potentials is correct?

Accepted Answer

The change in membrane potential is proportional to the strength of the stimulus.

Question 19

Which of the following is TRUE regarding the refractory period during an action potential?

Accepted Answer

During the relative refractory period, only a strong stimulus can initiate another action potential.

Question 20

Which of the following best explains why the effect of a neurotransmitter depends on the properties of the receptor rather than the nature of the neurotransmitter?

Accepted Answer

The same neurotransmitter can cause either depolarization or hyperpolarization depending on the receptor it binds to.

Nervous Tissue: Structure, Function, and Information Processing

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