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

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

Question 1

Which of the following best explains why the resting membrane potential of a neuron is typically negative?

Accepted Answer

The membrane is more permeable to potassium ions, which diffuse out of the cell, leaving behind negatively charged proteins.

Question 2

A neuron receives multiple graded potentials at its dendrites. Which scenario would most likely result in the generation of an action potential at the axon hillock?

Accepted Answer

The graded potentials are excitatory and summate to reach the threshold voltage.

Question 3

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

Accepted Answer

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

Question 4

During the absolute refractory period, a neuron cannot fire another action potential. What is the primary reason for this?

Accepted Answer

Sodium channels are inactivated and cannot reopen immediately.

Question 5

Which of the following best describes the 'all-or-none' principle of action potentials?

Accepted Answer

Action potentials only occur if the membrane potential reaches threshold, and their amplitude is always the same.

Question 6

A patient is experiencing pain after a heart attack. Which type of pain is this most likely classified as?

Accepted Answer

Referred pain

Question 7

Which of the following statements about graded potentials is correct?

Accepted Answer

Graded potentials can be depolarizing or hyperpolarizing and vary in magnitude.

Question 8

Which cell type is responsible for generating action potentials that control the contraction of the heart?

Accepted Answer

Pacemaker cells

Question 9

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

Accepted Answer

They continue to fire as long as the stimulus is present, allowing detection of prolonged stimuli.

Question 10

A person enters a dark room and gradually becomes able to see. Which type of receptor adaptation is most likely responsible for this change?

Accepted Answer

Tonic adaptation

Question 11

Which cranial nerve is responsible for purely sensory input related to vision?

Accepted Answer

Optic nerve

Question 12

Which of the following best explains why referred pain occurs?

Accepted Answer

Pain signals from internal organs are transmitted along the same pathways as those from the skin.

Question 13

Which of the following is a correct statement about the role of the somatosensory cortex?

Accepted Answer

It allocates more space to body regions with higher sensory input, such as the lips and hands.

Question 14

Which of the following is true regarding the permeability of the neuronal membrane at rest?

Accepted Answer

It is more permeable to potassium ions than sodium ions.

Question 15

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

Accepted Answer

They detect changes in temperature and pain.

Question 16

A patient has damage to the pacemaker cells in the heart. Which of the following symptoms would most likely result?

Accepted Answer

Irregular heart rhythm

Question 17

Which of the following is a consequence of prolonged opening of chloride channels in neurons?

Accepted Answer

Hyperpolarization, making the neuron less likely to fire an action potential

Question 18

Which of the following best describes the role of the cerebellum in motor control?

Accepted Answer

It coordinates and fine-tunes movements, especially tracking moving objects or performing complex tasks.

Question 19

Which of the following is a function of endothelial cells in blood vessels?

Accepted Answer

They line the interior of blood vessels and regulate exchange between blood and tissues.

Question 20

A neuron is exposed to a drug that increases the permeability of its membrane to sodium ions. What is the most likely effect on the neuron's membrane potential?

Accepted Answer

The membrane potential will become less negative (depolarized).

Resting Membrane Potential and Neural Signaling

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