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

$$E = \frac{RT}{zF} \ln \left( \frac{[\text{ion}]_{\text{outside}}}{[\text{ion}]_{\text{inside}}} \right)$$

Question 1

Which of the following best describes the resting membrane potential in a typical neuron?

Accepted Answer

It is mainly established by the sodium-potassium pump, ion channels, and selective permeability of the cell membrane.

Question 2

A patient is exposed to a toxin that prolongs the opening of chloride channels in their neurons. What is the most likely effect on their action potentials?

Accepted Answer

Action potentials will be inhibited due to hyperpolarization of the membrane.

Question 3

Which principle states that an action potential either occurs fully or not at all, once threshold is reached?

Accepted Answer

All-or-None Principle

Question 4

During the relative refractory period, which of the following is true about the generation of a new action potential?

Accepted Answer

A new action potential can be generated, but only if the stimulus is stronger than usual.

Question 5

Which of the following best explains why graded potentials differ from action potentials?

Accepted Answer

Graded potentials vary in magnitude depending on stimulus strength, while action potentials are all-or-none.

Question 6

A researcher observes that a neuron is unable to fire a second action potential, no matter how strong the stimulus, immediately after firing the first. This period is known as:

Accepted Answer

Absolute refractory period

Question 7

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

Accepted Answer

$$E = \frac{RT}{zF} \ln \left( \frac{[	ext{ion}]_{	ext{outside}}}{[	ext{ion}]_{	ext{inside}}} ight)$$

Question 8

Which of the following is a function of pacemaker cells in cardiac muscle?

Accepted Answer

They generate action potentials without external input.

Question 9

A person touches a hot stove and immediately withdraws their hand. Which type of receptor is primarily responsible for detecting this painful stimulus?

Accepted Answer

Nociceptor

Question 10

Which cranial nerve is purely sensory and responsible for the sense of smell?

Accepted Answer

Olfactory nerve

Question 11

A patient with a myocardial infarction reports pain radiating to their left arm. This phenomenon is best explained by:

Accepted Answer

Referred pain

Question 12

Which of the following best describes the role of tonic receptors?

Accepted Answer

They continue to respond during prolonged or continuous stimulation.

Question 13

Which of the following is true about the graded potential generated at a synapse?

Accepted Answer

Its magnitude depends on the amount of neurotransmitter released.

Question 14

Which of the following best explains the concept of sensory cortex representation?

Accepted Answer

The sensory cortex allocates more space to body parts with greater sensitivity.

Question 15

Which of the following is a correct statement about the pacemaker cells in the heart?

Accepted Answer

They spontaneously generate action potentials to regulate heart rhythm.

Question 16

Which of the following best describes the function of the sodium-potassium pump in maintaining the resting membrane potential?

Accepted Answer

It moves sodium ions out of the cell and potassium ions into the cell.

Question 17

A neuron receives multiple subthreshold graded potentials in rapid succession. What is the most likely outcome?

Accepted Answer

The neuron will fire an action potential due to temporal summation.

Question 18

Which of the following best describes the role of free nerve endings in the skin?

Accepted Answer

They detect changes in temperature and pain.

Question 19

Which of the following is most likely to occur if the extracellular potassium concentration increases significantly?

Accepted Answer

The neuron will become depolarized and more excitable.

Question 20

Which of the following best explains why action potentials do not summate like graded potentials?

Accepted Answer

Action potentials are all-or-none events and have refractory periods that prevent summation.

Neurophysiology: Resting Membrane Potential and Neural Signaling

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