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

$$E = \frac{RT}{zF} \ln \frac{[\text{ion outside}]}{[\text{ion inside}]}$$

Question 1

Which of the following best describes the primary contributors to the resting membrane potential in neurons?

Accepted Answer

The sodium-potassium pump, ion channels, and selective permeability of the cell membrane.

Question 2

A neuron is exposed to a stimulus that is just strong enough to reach threshold. What principle ensures that the neuron will fire an action potential?

Accepted Answer

All-or-none principle

Question 3

Which of the following best explains why a neuron cannot immediately fire a second action potential after the first?

Accepted Answer

The neuron is in the absolute refractory period, during which sodium channels are inactivated.

Question 4

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

Accepted Answer

$$E = \frac{RT}{zF} \ln \frac{[	ext{ion outside}]}{[	ext{ion inside}]}$$

Question 5

A patient is unable to track moving objects with their eyes. Which brain structure is most likely affected?

Accepted Answer

The cerebellum, which coordinates eye movements and tracking.

Question 6

Which of the following scenarios best illustrates the function of tonic receptors?

Accepted Answer

A person’s sensitivity to light increases after spending time in a dark room.

Question 7

Which of the following is true about graded potentials?

Accepted Answer

They vary in magnitude depending on the strength of the stimulus.

Question 8

During the relative refractory period, which ion movement is primarily responsible for the increased threshold needed to generate another action potential?

Accepted Answer

Efflux of potassium ions ($$K^+)$$

Question 9

Which of the following best describes the function of pacemaker cells in cardiac muscle?

Accepted Answer

They spontaneously generate action potentials without external input.

Question 10

A person experiences pain in their heart after a heart attack. What is the best explanation for this phenomenon?

Accepted Answer

The pain is referred pain, where pain from the heart is felt in another area due to shared neural pathways.

Question 11

Which of the following is a correct statement about hyperpolarization in neurons?

Accepted Answer

It is caused by prolonged opening of chloride channels, making the neuron more difficult to excite.

Question 12

Which of the following best describes the function of free nerve endings?

Accepted Answer

They are responsible for detecting changes in temperature and pain.

Question 13

Which of the following is true about the all-or-none principle of action potentials?

Accepted Answer

Action potentials only occur if the membrane potential reaches threshold.

Question 14

Which of the following best explains why the brain allocates more space to the upper lip in the sensory cortex?

Accepted Answer

The upper lip has a higher density of sensory receptors.

Question 15

Which of the following is a function of the pure sensory cranial nerve?

Accepted Answer

Transmitting sensory information from the eyes to the brain.

Question 16

Which of the following best describes the role of the pacemaker cells in the heart?

Accepted Answer

They generate action potentials that initiate the heartbeat.

Question 17

Which of the following is a characteristic of graded potentials?

Accepted Answer

They can summate to reach threshold and trigger an action potential.

Question 18

Which of the following best explains the function of the absolute refractory period?

Accepted Answer

It prevents the neuron from firing another action potential until sodium channels reset.

Question 19

Which of the following best describes the function of the cerebellum in the brain?

Accepted Answer

It coordinates voluntary movements, especially tracking moving objects.

Question 20

Which of the following is true about the role of the sodium-potassium pump in maintaining the resting membrane potential?

Accepted Answer

It actively transports $$3$$ sodium ions out and $$2$$ potassium ions into the cell, maintaining a negative charge inside.

Resting Membrane Potential and Neural Signaling

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