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

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

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 required to trigger an action potential. According to the all-or-none principle, what will happen?

Accepted Answer

No action potential will occur

Question 3

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

Accepted Answer

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

Question 4

During the hyperpolarization phase of an action potential, which ion movement is primarily responsible?

Accepted Answer

Efflux of potassium ions

Question 5

Which statement best explains the significance of the refractory period in neurons?

Accepted Answer

It prevents the backward propagation of action potentials and ensures one-way transmission

Question 6

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

Accepted Answer

Referred pain

Question 7

Which of the following is a property of graded potentials that distinguishes them from action potentials?

Accepted Answer

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

Question 8

Which type of receptor is most likely to adapt quickly to a constant stimulus, such as the feeling of clothing on your skin?

Accepted Answer

Phasic receptor

Question 9

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

Accepted Answer

Optic nerve

Question 10

A scientist is studying the effect of extracellular potassium concentration on the resting membrane potential. If the extracellular potassium concentration increases, what will happen to the resting membrane potential?

Accepted Answer

It will become less negative (depolarized)

Question 11

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

Accepted Answer

They generate action potentials spontaneously to regulate heart rhythm

Question 12

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

Accepted Answer

Once threshold is reached, an action potential of fixed size is generated

Question 13

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 has a higher density of sensory receptors, requiring more cortical representation

Question 14

Which of the following is a function of free nerve endings in the skin?

Accepted Answer

Detecting changes in temperature and pain

Question 15

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

Accepted Answer

Tonic receptor

Question 16

Which of the following best describes the function of the Purkinje fibers in the heart?

Accepted Answer

They conduct electrical signals rapidly to coordinate ventricular contraction

Question 17

Which of the following is a correct statement about the permeability of the neuronal membrane at rest?

Accepted Answer

It is more permeable to potassium ions than sodium ions

Question 18

A patient reports pain in the left arm during a heart attack. Which mechanism best explains this phenomenon?

Accepted Answer

Convergence of visceral and somatic sensory pathways in the spinal cord

Question 19

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

Accepted Answer

It moves sodium ions out of the cell and potassium ions into the cell, maintaining a negative internal environment

Question 20

Which equation represents the Goldman-Hodgkin-Katz (GHK) equation for membrane potential?

Accepted Answer

$$V_m = \frac{RT}{F} \ln \left( \frac{P_{K^+}[K^+]_{	ext{out}} + P_{Na^+}[Na^+]_{	ext{out}} + P_{Cl^-}[Cl^-]_{	ext{in}}}{P_{K^+}[K^+]_{	ext{in}} + P_{Na^+}[Na^+]_{	ext{in}} + P_{Cl^-}[Cl^-]_{	ext{out}}} ight)$$

Membrane Potentials and Neural Signaling: Key Concepts for General Chemistry

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