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 sodium ions out of the neuron and 2 potassium ions into the neuron, maintaining a negative membrane potential.

Question 2

A toxin blocks voltage-gated sodium channels in neurons. What would be the most immediate effect on neuronal signaling?

Accepted Answer

Action potentials would fail to initiate, preventing signal transmission.

Question 3

Which equation correctly represents the Nernst equation for calculating the equilibrium potential for an ion?

Accepted Answer

$$E_{ion} = \frac{RT}{zF} \ln \left( \frac{[ion]_{out}}{[ion]_{in}} \right)$$

Question 4

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

Accepted Answer

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

Question 5

Which of the following best explains why myelinated axons conduct action potentials more rapidly than unmyelinated axons?

Accepted Answer

Myelin allows action potentials to jump between nodes of Ranvier in a process called saltatory conduction.

Question 6

A neuron receives two excitatory postsynaptic potentials (EPSPs) in rapid succession at the same synapse. This is an example of:

Accepted Answer

Temporal summation

Question 7

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

Accepted Answer

Acetylcholine

Question 8

If the extracellular concentration of potassium ions increases significantly, what is the most likely effect on the resting membrane potential?

Accepted Answer

The resting membrane potential becomes less negative (depolarized).

Question 9

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

Accepted Answer

Action potential arrives at axon terminal → Voltage-gated Ca$$^{2+}$$ channels open → Neurotransmitter released → Neurotransmitter binds to postsynaptic receptors

Question 10

Which of the following best describes the 'all-or-none' property of action potentials?

Accepted Answer

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

Question 11

Which of the following would most likely result from a drug that blocks the reuptake of neurotransmitters from the synaptic cleft?

Accepted Answer

Increased duration of postsynaptic signaling

Question 12

Which of the following is true regarding graded potentials?

Accepted Answer

They decrease in magnitude with distance from the stimulus.

Question 13

A neuron is exposed to a drug that selectively opens potassium channels. What is the most likely effect on the membrane potential?

Accepted Answer

The neuron will hyperpolarize.

Question 14

Which of the following is a function of inhibitory neurotransmitters such as GABA?

Accepted Answer

They hyperpolarize the postsynaptic membrane, making action potentials less likely.

Question 15

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

Accepted Answer

Voltage-gated sodium channels become inactivated during the refractory period, preventing backward propagation.

Question 16

Which of the following is the correct formula for the Goldman-Hodgkin-Katz equation for membrane potential?

Accepted Answer

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

Question 17

Which of the following is a direct result of the opening of voltage-gated calcium channels at the axon terminal?

Accepted Answer

Release of neurotransmitter into the synaptic cleft

Question 18

Which of the following best describes the effect of summation of excitatory and inhibitory postsynaptic potentials (EPSPs and IPSPs) at the axon hillock?

Accepted Answer

The combined effect determines whether the threshold for an action potential is reached.

Neurons, Synapses, and Signaling: Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards