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

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

Question 1

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

Accepted Answer

It is mainly established by the selective permeability of the cell membrane to potassium ions and the activity of the sodium-potassium pump.

Question 2

A neuron is exposed to a stimulus that causes a rapid influx of sodium ions. What is most likely to occur next?

Accepted Answer

The membrane potential will depolarize, possibly triggering an action potential if threshold is reached.

Question 3

Which statement best explains the 'all-or-none' principle of action potentials?

Accepted Answer

Once threshold is reached, an action potential of fixed size is generated, regardless of stimulus strength.

Question 4

During the relative refractory period, which of the following is true?

Accepted Answer

A stronger-than-normal stimulus is required to generate an action potential.

Question 5

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

Accepted Answer

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

Question 6

A patient is experiencing muscle weakness due to a genetic mutation that causes prolonged 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 7

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

Accepted Answer

They spontaneously generate action potentials that regulate the heartbeat.

Question 8

Which of the following is a correct statement about graded potentials?

Accepted Answer

Graded potentials can vary in amplitude and may be either depolarizing or hyperpolarizing.

Question 9

A researcher is studying sensory neurons that respond to changes in temperature and pain. Which type of receptor is she most likely investigating?

Accepted Answer

Free nerve endings

Question 10

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

Accepted Answer

Olfactory nerve

Question 11

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 contains a higher density of sensory receptors.

Question 12

Which of the following is true about tonic receptors?

Accepted Answer

They maintain a sustained response to continuous stimuli.

Question 13

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

Free nerve ending

Question 14

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

Accepted Answer

It actively transports sodium out of the cell and potassium into the cell, maintaining a negative membrane potential.

Question 15

Which of the following scenarios would most likely result in hyperpolarization of a neuron?

Accepted Answer

Opening of chloride channels

Question 16

Which of the following is a key difference between graded potentials and action potentials?

Accepted Answer

Graded potentials can summate, while action potentials cannot.

Question 17

Which of the following best describes the refractory period in neurons?

Accepted Answer

It is the time after an action potential when the neuron is less responsive to stimuli.

Question 18

A patient with a heart attack is experiencing pain in their left arm. What is the best explanation for this phenomenon?

Accepted Answer

The pain is referred from the heart to the arm due to shared neural pathways.

Question 19

Which of the following best describes the function of the blood-brain barrier?

Accepted Answer

It restricts the entry of certain ions and molecules, protecting the brain from toxins.

Membrane Potentials and Sensory Receptors in Physiology

Study Guide - Practice Questions

Study Guide - Flashcards