Q: Which of the following statements best describes the function of the sodium-potassium exchange pump in maintaining the membrane potential of a neuron?

It uses active transport to move 3 Na\textsuperscript{+} ions out of the cell and 2 K\textsuperscript{+} ions into the cell, making the membrane more negative.

Q: During the repolarization phase of an action potential, which of the following events occurs?

Opening of K\textsuperscript{+} channels and efflux of potassium ions

Question 1

Which of the following statements best describes the function of the sodium-potassium exchange pump in maintaining the membrane potential of a neuron?

Accepted Answer

It uses active transport to move 3 Na	extsuperscript{+} ions out of the cell and 2 K	extsuperscript{+} ions into the cell, making the membrane more negative.

Question 2

A patient presents with progressive loss of sensation and motor control. MRI reveals demyelination in the CNS. Which neuroglial cell is most likely affected?

Accepted Answer

Oligodendrocyte

Question 3

Which of the following best explains why action potentials only travel in one direction along an axon?

Accepted Answer

The refractory period prevents the plasma membrane from responding to additional depolarizing stimuli immediately after an action potential.

Question 4

Which equation correctly represents the Nernst equation for calculating the equilibrium potential ($$E_{ion}) of an $$ion across a membrane?

Accepted Answer

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

Question 5

Which structural classification of neurons is most commonly found in sensory neurons of the peripheral nervous system?

Accepted Answer

Unipolar

Question 6

During the repolarization phase of an action potential, which of the following events occurs?

Accepted Answer

Opening of K	extsuperscript{+} channels and efflux of potassium ions

Question 7

A patient is unable to coordinate voluntary muscle contractions. Which division of the nervous system is most likely impaired?

Accepted Answer

Somatic nervous system

Question 8

Which of the following best describes the role of astrocytes in the CNS?

Accepted Answer

They maintain the blood-brain barrier and regulate the interstitial environment.

Question 9

Which of the following is TRUE regarding graded (local) potentials?

Accepted Answer

They decrease in strength as they spread from the site of stimulation.

Question 10

Which neurotransmitter is released at cholinergic synapses and what is its effect on the postsynaptic membrane?

Accepted Answer

Acetylcholine (ACh); depolarizes the postsynaptic membrane

Question 11

Which type of ion channel opens in response to physical distortion of the membrane surface, such as pressure or vibration?

Accepted Answer

Mechanically gated ion channel

Question 12

Which of the following best explains why myelinated axons conduct action potentials faster than unmyelinated axons?

Accepted Answer

Action potentials jump from node to node (saltatory conduction), reducing the number of times the membrane must depolarize.

Question 13

Which of the following is a function of microglia in the central nervous system?

Accepted Answer

Engulf cellular debris, wastes, and pathogens

Question 14

A patient is exposed to carbon monoxide, which acts as a dissolved gas neurotransmitter. What is the most likely effect?

Accepted Answer

Automobile exhaust exposure leading to exogenous neurotransmitter effects

Question 15

Which of the following best describes the difference between inotropic and metabotropic receptors?

Accepted Answer

Inotropic receptors directly affect the receptor, while metabotropic receptors act indirectly through GPCRs.

Question 16

Which of the following is TRUE regarding synaptic fatigue?

Accepted Answer

It occurs when neurotransmitter synthesis and transport mechanisms cannot keep up with demand after prolonged or intense stimulation.

Question 17

Which of the following best describes the function of ependymal cells in the CNS?

Accepted Answer

They assist in producing and monitoring cerebrospinal fluid (CSF).

Question 18

Which of the following is a characteristic of tonic receptors?

Accepted Answer

They are always active and generate action potentials at a frequency that reflects the background level of stimulation.

Question 19

Which of the following best describes the role of Nissl bodies in neurons?

Accepted Answer

They are clusters of RER and free ribosomes involved in protein synthesis.

Question 20

Which of the following is TRUE regarding the axonal transport in neurons?

Accepted Answer

Both anterograde and retrograde transport occur simultaneously in axons.

Comprehensive Study Notes: Nervous System Structure and Function

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