Q: What is the primary function of the sodium-potassium pump (Na$^{+}$/K$^{+}$ ATPase) in neurons?

To actively transport Na$^{+}$ out and K$^{+}$ into the cell, maintaining the resting membrane potential.

Question 1

Which of the following best describes the function of oligodendrocytes in the central nervous system?

Accepted Answer

They form myelin sheaths around axons, increasing the speed of nerve impulse conduction.

Question 2

A patient presents with muscle weakness and slowed reflexes. Demyelination is suspected. Which cell type is most likely affected in the peripheral nervous system?

Accepted Answer

Schwann cells

Question 3

Which of the following ions has the highest concentration inside a typical neuron at rest?

Accepted Answer

K$^{+}$

Question 4

What is the primary function of the sodium-potassium pump (Na$^{+}$/K$^{+}$ ATPase) in neurons?

Accepted Answer

To actively transport Na$^{+}$ out and K$^{+}$ into the cell, maintaining the resting membrane potential.

Question 5

Which of the following best explains why action potentials are 'all-or-none' events?

Accepted Answer

Once threshold is reached, the action potential always occurs with the same amplitude.

Question 6

A neuron receives multiple graded potentials at its dendrites. Which process allows these signals to combine and potentially trigger an action potential?

Accepted Answer

Summation

Question 7

Which of the following best describes saltatory conduction?

Accepted Answer

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

Question 8

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

Accepted Answer

No stimulus, regardless of strength, can trigger another action potential.

Question 9

Which neurotransmitter is most closely associated with inhibitory postsynaptic potentials (IPSPs) in the central nervous system?

Accepted Answer

GABA

Question 10

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

Accepted Answer

Neurons will be unable to generate action potentials.

Question 11

Which of the following best describes the role of astrocytes in the central nervous system?

Accepted Answer

They regulate the extracellular environment and support neurons.

Question 12

Which of the following is a characteristic of graded potentials?

Accepted Answer

They decrease in amplitude as they spread from the site of origin.

Question 13

Which of the following best explains why myelination increases the speed of nerve impulse conduction?

Accepted Answer

It allows action potentials to jump between nodes of Ranvier.

Question 14

Which of the following neurotransmitters is classified as a catecholamine and is derived from the amino acid tyrosine?

Accepted Answer

Dopamine

Question 15

A neuron is stimulated by multiple excitatory postsynaptic potentials (EPSPs) in rapid succession at the same synapse. What is this process called?

Accepted Answer

Temporal summation

Question 16

Which of the following best describes the function of microglia in the central nervous system?

Accepted Answer

They act as immune cells, removing debris and pathogens.

Question 17

Which of the following is true regarding the difference between leakage channels and gated channels in neurons?

Accepted Answer

Gated channels open in response to specific stimuli, while leakage channels are always open.

Question 18

Which of the following factors would most likely increase the conduction velocity of an action potential along an axon?

Accepted Answer

Increasing axon diameter and adding myelin

Question 19

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 initiated if threshold is reached.

Question 20

A patient has a genetic mutation that impairs the function of voltage-gated K$^{+}$ channels. Which phase of the action potential would be most affected?

Accepted Answer

Repolarization

Chapter 11: The Nervous System – Structure and Function Study Notes

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