Question 1

Which of the following best describes the main function of the central nervous system (CNS)?

Accepted Answer

Processes and integrates information received from sensory receptors and coordinates responses.

Question 2

A patient presents with muscle weakness after excessive sweating and drinking only water. Which physiological principle explains this symptom?

Accepted Answer

Hypokalemia causes the resting membrane potential to move further from threshold, making action potentials less likely to fire.

Question 3

Which equation predicts the membrane potential for a single ion, and which equation predicts membrane potential using multiple ions?

Accepted Answer

Nernst equation for a single ion, GHK equation for multiple ions.

Question 4

Which of the following is TRUE regarding action potentials?

Accepted Answer

Action potentials are an all-or-none phenomenon.

Question 5

What is the primary ion responsible for the resting membrane potential in neurons, and why?

Accepted Answer

Potassium, because there are more leak potassium channels than sodium or calcium channels.

Question 6

A graded potential is generated at the dendrites of a neuron. Which of the following best describes why it loses strength as it travels toward the trigger zone?

Accepted Answer

Current leak and cytoplasmic resistance cause the graded potential to diminish.

Question 7

Which of the following best describes the process of saltatory conduction?

Accepted Answer

Action potentials jump from node to node, being refreshed at each node of Ranvier.

Question 8

During the absolute refractory period, which of the following is TRUE?

Accepted Answer

Voltage-gated sodium channels are inactivated and cannot be opened.

Question 9

Which of the following is a characteristic of excitatory postsynaptic potentials (EPSPs)?

Accepted Answer

They depolarize the postsynaptic membrane, making action potentials more likely.

Question 10

Which of the following best explains how neurons encode the intensity of a stimulus?

Accepted Answer

By increasing the frequency of action potentials.

Question 11

Which of the following is NOT a way that neurotransmitter activity is terminated?

Accepted Answer

All of the above are ways that neurotransmitter activity is terminated.

Question 12

Which of the following best describes the effect of hyperkalemia on neuron function?

Accepted Answer

It shifts the resting membrane potential closer to threshold, making neurons more excitable.

Question 13

Which of the following is FALSE regarding graded potentials?

Accepted Answer

They are an all-or-none phenomenon.

Question 14

Which of the following is a function of the nodes of Ranvier?

Accepted Answer

Refresh electrical signals along an axon.

Question 15

Which of the following best describes the effect of a depolarizing graded potential reaching the trigger zone?

Accepted Answer

If it reaches threshold, voltage-gated sodium channels open and an action potential is initiated.

Question 16

Which of the following is TRUE regarding the ligand-gated ion channel receptors?

Accepted Answer

They cause fast synaptic potentials, including EPSPs and IPSPs.

Question 17

Which of the following is a characteristic of fast axonal transport?

Accepted Answer

It uses stationary microtubules as tracks and motor proteins with ATP to move vesicles rapidly.

Question 18

Which of the following best describes spatial summation?

Accepted Answer

Summation of graded potentials that originate at different locations on the neuron.

Question 19

Which of the following is a characteristic of G protein-linked neurotransmitter receptors?

Accepted Answer

They activate second messenger systems, resulting in slow synaptic potentials.

Nervous System Physiology: Structure, Function, and Signal Transmission

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