Q: Which equation best represents the Nernst equation for calculating the equilibrium potential for a specific 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 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 below the threshold for generating an action potential. Which principle explains why no action potential occurs?

Accepted Answer

All-or-None Principle

Question 3

During which period is it impossible for a neuron to generate another action potential, regardless of the strength of the stimulus?

Accepted Answer

Absolute Refractory Period

Question 4

Which of the following best explains why action potentials are unidirectional along an axon?

Accepted Answer

The absolute refractory period prevents the action potential from traveling backward.

Question 5

A patient is experiencing pain after a heart attack. Which term best describes this phenomenon?

Accepted Answer

Referred Pain

Question 6

Which of the following is a characteristic of graded potentials?

Accepted Answer

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

Question 7

Which type of receptor is most likely to be involved in the heightened sensitivity to light after entering a dark room?

Accepted Answer

Tonic Receptors

Question 8

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 9

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

Accepted Answer

An action potential either occurs fully or not at all, once threshold is reached.

Question 10

Which of the following best explains why the brain allocates more space to the upper lip, tongue, and hands in the somatosensory cortex?

Accepted Answer

These areas have a higher density of sensory receptors.

Question 11

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

Accepted Answer

The superior colliculi

Question 12

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

Accepted Answer

They detect changes in temperature and pain.

Question 13

Which of the following statements about hyperpolarization is correct?

Accepted Answer

It is caused by prolonged opening of chloride channels, making the neuron less likely to generate an action potential.

Question 14

Which equation best represents the Nernst equation for calculating the equilibrium potential for a specific ion?

Accepted Answer

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

Question 15

A toxin blocks the sodium-potassium pump in a neuron. What is the most likely immediate effect on the resting membrane potential?

Accepted Answer

The resting membrane potential will become less negative (depolarize).

Question 16

Which of the following is a real-life example of referred pain?

Accepted Answer

Pain felt in the left arm during a heart attack

Question 17

Which of the following best describes the function of photoreceptors in the eye?

Accepted Answer

They convert light energy into electrical signals.

Question 18

A patient has damage to a purely sensory cranial nerve. Which of the following symptoms would you expect?

Accepted Answer

Loss of sensation in the area innervated by the nerve

Question 19

Which of the following best explains why the relative refractory period occurs after an action potential?

Accepted Answer

Some sodium channels are still inactivated and potassium channels remain open, requiring a stronger stimulus to generate another action potential.

Membrane Potentials and Neural Signaling: Key Concepts

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