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 neuron receives simultaneous excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic potentials (IPSPs). Which of the following best describes the outcome at the axon hillock?

Accepted Answer

The summation of EPSPs and IPSPs determines whether the membrane potential reaches threshold for an action potential.

Question 3

Which equation correctly relates voltage ($$V$$), current ($$I$$), and resistance ($$R) in an $$electrical circuit, as applied to the resting membrane potential?

Accepted Answer

$$V = I 	imes R$$

Question 4

During the depolarization phase of an action potential, which ion channel opens and what is the direction of ion movement?

Accepted Answer

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

Question 5

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

Accepted Answer

Action potentials jump from node to node via saltatory conduction, increasing speed.

Question 6

Which of the following is TRUE regarding the absolute refractory period of a neuron?

Accepted Answer

No action potential can be initiated, regardless of stimulus strength.

Question 7

A patient is experiencing muscle weakness due to a defect in the sodium-potassium pump. Which of the following best describes the effect on the resting membrane potential?

Accepted Answer

The resting membrane potential moves closer to zero due to disrupted ion gradients.

Question 8

Which of the following best describes the difference between chemically-gated and voltage-gated ion channels?

Accepted Answer

Chemically-gated channels open in response to neurotransmitter binding, while voltage-gated channels open in response to changes in membrane potential.

Question 9

Which of the following best explains the effect of axon diameter on the speed of action potential conduction?

Accepted Answer

Larger axon diameter decreases resistance, allowing faster conduction.

Question 10

A graded potential is generated at a dendrite. Which of the following factors will NOT affect its amplitude?

Accepted Answer

The presence of myelin at the dendrite.

Question 11

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

Accepted Answer

They maintain the blood-brain barrier and regulate the extracellular environment.

Question 12

Which of the following is a correct statement about the distribution of ions across the neuronal membrane at rest?

Accepted Answer

There is a higher concentration of $$Na^+$$ outside the cell and $$K^+$$ inside the cell.

Question 13

Which of the following best describes the process of continuous conduction in unmyelinated axons?

Accepted Answer

Action potentials are regenerated at every point along the axon.

Question 14

Which of the following is TRUE regarding the function of the sodium-potassium pump in neurons?

Accepted Answer

It moves $$3$$ $$Na^+$$ out and $$2$$ $$K^+ in$$, maintaining the resting membrane potential.

Question 15

A patient is given a drug that blocks voltage-gated sodium channels. What is the most likely effect on neuronal signaling?

Accepted Answer

Action potentials will be unable to initiate or propagate.

Question 16

Which of the following best describes the effect of spatial summation at a postsynaptic neuron?

Accepted Answer

Multiple graded potentials from different synapses combine to influence the membrane potential.

Question 17

Which of the following is a function of Schwann cells in the peripheral nervous system?

Accepted Answer

They form myelin sheaths around axons, facilitating saltatory conduction.

Question 18

Which of the following best explains the difference between afferent and efferent divisions of the peripheral nervous system?

Accepted Answer

Afferent division carries sensory information to the CNS; efferent division carries motor commands to effectors.

Question 19

Which of the following best describes the role of inhibitory postsynaptic potentials (IPSPs) in neuronal signaling?

Accepted Answer

IPSPs hyperpolarize the postsynaptic membrane, decreasing the likelihood of an action potential.

Fundamentals of the Nervous System and Nervous Tissue: Key Concepts and Study Guide

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