Question 1

Which of the following best describes the primary function of dendrites in a neuron?

Accepted Answer

Receive signals from other neurons and convey them to the cell body

Question 2

The resting potential of a neuron is primarily established by the concentration gradients of which ions?

Accepted Answer

Potassium (K$$^{+}) $$and sodium (Na$$^{+})$$

Question 3

Which equation is used to calculate the equilibrium potential for a particular ion across a neuron's membrane?

Accepted Answer

$$E_{ion} = 62 \mathrm{mV} \log \frac{[ion]_{outside}}{[ion]_{inside}}$$

Question 4

What is the main role of voltage-gated sodium (Na$$^{+}) $$channels during the generation of an action potential?

Accepted Answer

They open in response to depolarization, allowing Na$$^{+}$$ ions to flow into the neuron, causing further depolarization.

Question 5

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

Accepted Answer

Activated Na$$^{+}$$ channels and the refractory period prevent the action potential from moving backward.

Question 6

Saltatory conduction in myelinated axons is characterized by:

Accepted Answer

Action potentials jumping from one node of Ranvier to the next, increasing conduction speed.

Question 7

A patient is exposed to the nerve gas sarin, which disrupts acetylcholine transmission. What is the most likely physiological effect?

Accepted Answer

Paralysis due to inability of acetylcholine to stimulate muscle contraction.

Question 8

Which of the following is TRUE about the role of glial cells in the nervous system?

Accepted Answer

Glial cells support neurons and can outnumber them by up to 50-fold in the mammalian brain.

Question 9

Which of the following best describes an excitatory postsynaptic potential (EPSP)?

Accepted Answer

A depolarization that brings the membrane potential closer to threshold.

Question 10

Temporal summation at a synapse occurs when:

Accepted Answer

Two or more EPSPs are produced in rapid succession at the same synapse.

Question 11

Which of the following scenarios would most likely result in the generation of an action potential in a postsynaptic neuron?

Accepted Answer

The combined effect of multiple EPSPs through spatial and temporal summation reaches threshold at the axon hillock.

Question 12

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

Accepted Answer

Opening of the ion channel and generation of a postsynaptic potential

Question 13

During the falling phase of an action potential, which event occurs?

Accepted Answer

Voltage-gated K$$^{+}$$ channels open and K$$^{+}$$ flows out.

Question 14

Which of the following best explains the effect of a toxin that blocks voltage-gated K$$^{+}$$ channels in neurons?

Accepted Answer

The neuron would have prolonged action potentials due to delayed repolarization.

Question 15

Which of the following is a characteristic of metabotropic receptors at synapses?

Accepted Answer

They activate a signal transduction pathway involving second messengers.

Question 16

A neuron receives both excitatory and inhibitory inputs. What determines whether it will fire an action potential?

Accepted Answer

The summed effect of EPSPs and IPSPs at the axon hillock reaching threshold

Question 17

Which of the following best describes the role of the axon hillock in a neuron?

Accepted Answer

It is the region where action potentials are typically initiated.

Question 18

Which of the following would most likely increase the speed of action potential conduction in a neuron?

Accepted Answer

Increasing the diameter of the axon and adding a myelin sheath

Question 19

Which of the following is TRUE regarding the difference between the central nervous system (CNS) and peripheral nervous system (PNS)?

Accepted Answer

The CNS is composed of the brain and spinal cord, while the PNS consists of nerves and ganglia outside the CNS.

Chapter 37: Neurons, Synapses, and Signaling – Study Notes

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