Q: Which of the following equations correctly represents the Nernst equation for calculating the equilibrium potential for a monovalent ion at body temperature?

$$E = \frac{61}{z} \log \left( \frac{[\text{ion}]_{\text{outside}}}{[\text{ion}]_{\text{inside}}} \right)$$

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 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 less likely to occur due to hyperpolarization.

Question 3

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

Accepted Answer

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

Question 4

During which period is a neuron unable to generate another action potential, no matter how strong the stimulus?

Accepted Answer

Absolute refractory period

Question 5

Which of the following best describes graded potentials?

Accepted Answer

They vary in magnitude depending on stimulus strength and can be summed.

Question 6

A patient with a brain injury loses the ability to track moving objects with their eyes. Which brain region is most likely affected?

Accepted Answer

The superior colliculus

Question 7

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

Accepted Answer

They can spontaneously generate action potentials without external input.

Question 8

Which of the following best describes tonic receptors?

Accepted Answer

They continue to respond to prolonged or continuous stimuli, such as light adaptation.

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

Free nerve endings

Question 10

Which of the following equations correctly represents the Nernst equation for calculating the equilibrium potential for a monovalent ion at body temperature?

Accepted Answer

$$E = \frac{61}{z} \log \left( \frac{[	ext{ion}]_{	ext{outside}}}{[	ext{ion}]_{	ext{inside}}} ight)$$

Question 11

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

Accepted Answer

There is a greater permeability to potassium ions, which diffuse out of the cell, leaving behind negatively charged proteins.

Question 12

A patient is diagnosed with a condition that impairs the function of their sodium-potassium pumps. Which of the following would most likely occur?

Accepted Answer

The resting membrane potential would become less negative.

Question 13

Which of the following is an example of a graded potential?

Accepted Answer

A postsynaptic potential in a dendrite

Question 14

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

Accepted Answer

Olfactory nerve (Cranial Nerve I)

Question 15

Which of the following best describes the role of the brain's somatosensory cortex in touch perception?

Accepted Answer

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

Question 16

A patient with a heart attack reports pain in their left arm. This is an example of which phenomenon?

Accepted Answer

Referred pain

Question 17

Which of the following best explains why action potentials travel in only one direction along an axon?

Accepted Answer

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

Question 18

Which of the following is a function of endothelial cells in capillaries?

Accepted Answer

They regulate the flow of blood and maintain the blood-brain barrier.

Question 19

A neuron receives two subthreshold excitatory postsynaptic potentials (EPSPs) in rapid succession at the same synapse. What is this phenomenon called?

Accepted Answer

Temporal summation

Question 20

Which of the following best describes the effect of a local anesthetic that blocks voltage-gated sodium channels?

Accepted Answer

It prevents the generation and propagation of action potentials in sensory neurons.

Resting Membrane Potential and Action Potentials: Key Concepts for General Chemistry

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