Question 1

Which of the following best describes the function of the sodium-potassium pump ($$\mathrm{Na^+/K^+}$$ ATPase) in maintaining the resting membrane potential of a neuron?

Accepted Answer

It actively transports three $$\mathrm{Na^+}$$ ions out of the cell and two $$\mathrm{K^+}$$ ions into the cell, maintaining concentration gradients.

Question 2

A patient is exposed to a neurotoxin that uses retrograde axonal transport to reach the cell body. Which of the following best explains the mechanism of retrograde transport?

Accepted Answer

Movement of substances from the axon terminal toward the cell body.

Question 3

Which structure is responsible for forming myelin sheaths around axons in the central nervous system (CNS)?

Accepted Answer

Oligodendrocytes

Question 4

According to Ohm's law, which equation correctly relates current ($$I$$), voltage ($$V$$), and resistance ($$R) in $$neurons?

Accepted Answer

$$I = \dfrac{V}{R}$$

Question 5

Which of the following best describes the difference between a nucleus and a ganglion in nervous system terminology?

Accepted Answer

A nucleus is a collection of neuron cell bodies in the CNS; a ganglion is a collection of neuron cell bodies in the PNS.

Question 6

During the depolarization phase of an action potential, which ion channels open and what is the result?

Accepted Answer

Voltage-gated $$\mathrm{Na^+}$$ channels open, causing $$\mathrm{Na^+} to $$enter the cell.

Question 7

A neuron is at rest with a membrane potential of $$-70 mV. If $$the membrane becomes more negative, reaching $$-80 mV$$, what has occurred?

Accepted Answer

Hyperpolarization

Question 8

Which of the following is TRUE regarding graded potentials and action potentials?

Accepted Answer

Graded potentials decay with distance, while action potentials propagate without decrement.

Question 9

Which of the following would most likely increase the frequency of action potentials generated by a neuron?

Accepted Answer

Increasing the strength of the stimulus above threshold.

Question 10

Which type of ion channel opens in response to physical deformation of the receptor, such as pressure or stretch?

Accepted Answer

Mechanically gated channel

Question 11

A neuron receives simultaneous excitatory and inhibitory inputs. Which of the following best describes the outcome at the axon hillock?

Accepted Answer

The inputs are summed, and if the net effect reaches threshold, an action potential is generated.

Question 12

Which of the following best explains why the inside of a neuron is more negative than the outside at rest?

Accepted Answer

More $$\mathrm{K^+}$$ diffuses out of the cell than $$\mathrm{Na^+}$$ diffuses in, and large anionic proteins remain inside.

Question 13

Which of the following is a correct sequence of events during an action potential?

Accepted Answer

Resting state → Depolarization → Repolarization → Hyperpolarization

Question 14

Which of the following is TRUE about the absolute refractory period of a neuron?

Accepted Answer

No action potential can be generated, regardless of stimulus strength.

Question 15

Which of the following best describes the role of excitatory postsynaptic potentials (EPSPs)?

Accepted Answer

They depolarize the postsynaptic membrane, increasing the likelihood of action potential generation.

Question 16

Which of the following is a characteristic of chemical synapses?

Accepted Answer

Release of neurotransmitters into the synaptic cleft.

Question 17

Which of the following would most likely result from damage to oligodendrocytes in the CNS?

Accepted Answer

Impaired formation of myelin sheaths around CNS axons, leading to slower action potential conduction.

Question 18

Which equation correctly expresses the relationship between membrane potential ($$V_m$$), intracellular ($$[K^+]_{in}) $$and extracellular ($$[K^+]_{out}) $$potassium concentrations, using the Nernst equation?

Accepted Answer

$$V_m = \dfrac{RT}{F} \ln \left( \dfrac{[K^+]_{out}}{[K^+]_{in}} \right)$$

Question 19

A patient with multiple sclerosis experiences slowed nerve conduction. Which of the following best explains this phenomenon?

Accepted Answer

Loss of myelin sheaths, resulting in decreased speed of action potential propagation.

Fundamentals of the Nervous System and Nervous Tissue – Study Notes

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