Question 1

Which of the following best describes the role of the sodium-potassium pump in maintaining 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

Given the ion concentrations inside and outside a mammalian neuron (K+ inside: 140 mM, K+ outside: 5 mM), what is the equilibrium potential for potassium ($$E_K) at 37$$°C? Use the Nernst equation: $$E_K = \frac{62\ 	ext{mV}}{z} \log \frac{[K^+]_{	ext{outside}}}{[K^+]_{	ext{inside}}}$$, where $$z = +1$$ for K+.

Accepted Answer

$$E_K = -90\ 	ext{mV}$$

Question 3

Which of the following events occurs first during the rising phase of an action potential?

Accepted Answer

Voltage-gated Na+ channels open, allowing Na+ to enter the cell.

Question 4

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

Accepted Answer

Temporal summation; it increases the likelihood of an action potential.

Question 5

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

Accepted Answer

The refractory period inactivates Na+ channels behind the action potential.

Question 6

Which of the following is a direct result of neurotransmitter binding to a ligand-gated ion channel on the postsynaptic membrane?

Accepted Answer

The postsynaptic cell undergoes a change in membrane potential.

Question 7

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

Accepted Answer

Neurons will be unable to generate action potentials.

Question 8

Which glial cell type is responsible for forming the myelin sheath in the central nervous system (CNS)?

Accepted Answer

Oligodendrocytes

Question 9

What is the main advantage of saltatory conduction in myelinated axons?

Accepted Answer

It increases the speed of action potential propagation.

Question 10

Which of the following mechanisms is NOT involved in the termination of neurotransmitter signaling at a chemical synapse?

Accepted Answer

Continuous activation of ligand-gated ion channels

Question 11

A neuron has a resting membrane potential of $$-70\ 	ext{mV}. If $$the membrane becomes more permeable to Na+, what will happen to the membrane potential?

Accepted Answer

It will move toward the equilibrium potential for Na+ (depolarize).

Question 12

Which of the following best describes the function of interneurons in the nervous system?

Accepted Answer

They integrate and interpret information within the CNS.

Question 13

Which of the following is a property of action potentials but NOT graded potentials?

Accepted Answer

They are all-or-none events.

Question 14

A postsynaptic neuron receives both EPSPs and IPSPs from multiple presynaptic neurons. What determines whether the postsynaptic neuron will fire an action potential?

Accepted Answer

The sum of all EPSPs and IPSPs at the axon hillock

Question 15

Which of the following neurotransmitters is classified as a biogenic amine and is involved in mood regulation?

Accepted Answer

Serotonin

Question 16

Which of the following best describes the effect of a toxin that blocks the reuptake of neurotransmitters at the synaptic cleft?

Accepted Answer

It would prolong the effect of the neurotransmitter on the postsynaptic cell.

Question 17

Which of the following is a correct sequence of events for chemical synaptic transmission?

Accepted Answer

Action potential arrives at synaptic terminal → neurotransmitter released → neurotransmitter binds to postsynaptic receptor → postsynaptic potential generated

Question 18

Which of the following is a feature of metabotropic receptors but NOT ionotropic receptors?

Accepted Answer

They activate signal transduction pathways involving second messengers.

Question 19

A neuron is exposed to a drug that increases the permeability of the membrane to Cl-. What is the most likely effect on the postsynaptic potential?

Accepted Answer

It will generate an inhibitory postsynaptic potential (IPSP).

Neurons, Synapses, and Signaling: Structure and Function in Information Transfer

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