Q: Which equation is used to calculate the equilibrium potential for a specific ion across a membrane?

$$E_{ion} = 62\ \text{mV} \left( \log \frac{[\text{ion}]_{\text{outside}}}{[\text{ion}]_{\text{inside}}} \right)$$

Question 1

Which of the following best describes the role of the sodium-potassium pump in establishing the resting potential of a neuron?

Accepted Answer

It actively transports 3 Na+ out of the cell and 2 K+ into the cell using ATP.

Question 2

A neuron’s resting membrane potential is closest to the equilibrium potential of which ion, and why?

Accepted Answer

K+, because there are more K+ leak channels than Na+ leak channels.

Question 3

Which equation is used to calculate the equilibrium potential for a specific ion across a membrane?

Accepted Answer

$$E_{ion} = 62\ 	ext{mV} \left( \log \frac{[	ext{ion}]_{	ext{outside}}}{[	ext{ion}]_{	ext{inside}}} ight)$$

Question 4

What would happen to the resting membrane potential if the extracellular concentration of K+ were increased significantly?

Accepted Answer

The resting potential would become less negative (depolarized).

Question 5

During the rising phase of an action potential, which of the following occurs?

Accepted Answer

Voltage-gated Na+ channels open, causing Na+ to rush into the cell.

Question 6

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

Accepted Answer

The refractory period prevents the reopening of voltage-gated Na+ channels immediately behind the action potential.

Question 7

Saltatory conduction is faster than continuous conduction because:

Accepted Answer

Action potentials jump from one node of Ranvier to the next, skipping myelinated regions.

Question 8

Which of the following is a correct sequence of events at a chemical synapse?

Accepted Answer

Action potential arrives at synaptic terminal → Ca2+ influx → neurotransmitter release

Question 9

A postsynaptic potential that hyperpolarizes the postsynaptic membrane is called:

Accepted Answer

Inhibitory postsynaptic potential (IPSP)

Question 10

Which of the following mechanisms can terminate neurotransmitter signaling at a synapse?

Accepted Answer

All of the above

Question 11

Which type of glial cell is responsible for myelinating axons in the central nervous system (CNS)?

Accepted Answer

Oligodendrocytes

Question 12

Which of the following best describes the difference between ionotropic and metabotropic receptors at synapses?

Accepted Answer

Ionotropic receptors are ligand-gated ion channels that produce rapid responses, while metabotropic receptors activate slower, longer-lasting responses via second messengers.

Question 13

A patient is exposed to a toxin that blocks voltage-gated Na+ channels. What is the most likely effect on neuronal signaling?

Accepted Answer

Action potentials will not be initiated or propagated.

Question 14

Which of the following is NOT a function of glial cells?

Accepted Answer

Transmitting action potentials

Question 15

If a neuron receives two excitatory postsynaptic potentials (EPSPs) at the same synapse in rapid succession, what is this phenomenon called?

Accepted Answer

Temporal summation

Question 16

Which neurotransmitter is most directly involved in skeletal muscle contraction at the neuromuscular junction?

Accepted Answer

Acetylcholine

Question 17

Which of the following best explains why the resting potential is not exactly equal to the equilibrium potential for K+ ($$E_K$$)?

Accepted Answer

A small number of Na+ ions leak into the cell, making the resting potential slightly less negative than $$E_K.$$

Question 18

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

Accepted Answer

They can be depolarizing or hyperpolarizing and decrease in magnitude with distance.

Question 19

Which of the following best describes the function of sensory neurons?

Accepted Answer

They transmit information about external and internal stimuli to the nervous system.

Question 20

A neuron receives simultaneous EPSPs at two different synapses. What is this phenomenon called?

Accepted Answer

Spatial summation

Neurons, Synapses, and Signaling: Structure and Function of the Nervous System

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