Q: Which of the following equations correctly represents the Nernst equation for calculating the equilibrium potential for a monovalent ion at body temperature (37°C)?

$$E = \frac{61.5}{z} \log \left( \frac{[\text{ion}]_{\text{outside}}}{[\text{ion}]_{\text{inside}}} \right)$$

Question 1

Which of the following best describes the primary contributors to the resting membrane potential in neurons?

Accepted Answer

The sodium-potassium pump, selective permeability of the cell membrane, and ion channels.

Question 2

A neuron is exposed to a prolonged stimulus that keeps chloride channels open. What is the most likely effect on the neuron's ability to generate action potentials?

Accepted Answer

The neuron will become less likely to fire action potentials due to hyperpolarization.

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 occurs; subthreshold stimuli do not produce action potentials.

Question 4

During the relative refractory period, which of the following is true about the neuron's ability to fire another action potential?

Accepted Answer

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

Question 5

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

Accepted Answer

They generate action potentials that regulate the heartbeat without external input.

Question 6

A patient is unable to track moving objects with their eyes, but can still see stationary objects clearly. Which brain region is most likely affected?

Accepted Answer

The cerebellum, which coordinates voluntary movement and eye tracking.

Question 7

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

Accepted Answer

A postsynaptic potential that varies in magnitude depending on the amount of neurotransmitter released.

Question 8

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

Accepted Answer

Olfactory nerve

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

Nociceptors

Question 10

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

Accepted Answer

They continue to respond to a stimulus as long as it is present, adapting slowly.

Question 11

Which of the following equations correctly represents the Nernst equation for calculating the equilibrium potential for a monovalent ion at body temperature (37°C)?

Accepted Answer

$$E = \frac{61.5}{z} \log \left( \frac{[	ext{ion}]_{	ext{outside}}}{[	ext{ion}]_{	ext{inside}}} ight)$$

Question 12

A patient with a myocardial infarction (heart attack) reports pain in their left arm. This is an example of:

Accepted Answer

Referred pain, where pain is perceived at a location other than the site of the stimulus.

Question 13

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

Accepted Answer

These areas have a higher density of sensory receptors, requiring more cortical representation.

Question 14

Which of the following is true about the absolute refractory period of a neuron?

Accepted Answer

No stimulus, no matter how strong, can initiate another action potential during this period.

Question 15

Which of the following best describes the role of endothelial cells in capillaries?

Accepted Answer

They line the capillaries and regulate the flow of materials between blood and tissues.

Question 16

A person enters a dark room and, after several minutes, can see better. Which type of receptor adaptation is responsible for this change?

Accepted Answer

Sensory receptor adaptation to prolonged stimulus

Question 17

Which of the following best describes the difference between graded potentials and action potentials?

Accepted Answer

Graded potentials vary in magnitude and can summate, while action potentials are all-or-none and do not summate.

Question 18

Which of the following best explains why the sodium-potassium pump is essential for maintaining the resting membrane potential?

Accepted Answer

It actively transports 3 sodium ions out and 2 potassium ions into the cell, maintaining the concentration gradients.

Question 19

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

Accepted Answer

Temporal summation; the EPSPs can combine to reach threshold and trigger an action potential.

Membrane Potentials and Sensory Receptors: Key Concepts for General Chemistry and Physiology

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