Question 1

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

Accepted Answer

Myelin allows for saltatory conduction, where action potentials jump between nodes of Ranvier.

Question 2

Which neuroglial cell is primarily responsible for phagocytosis of microbes and cellular debris in the central nervous system?

Accepted Answer

Microglia

Question 3

A patient has a demyelinating disease affecting the central nervous system. Which cell type is most likely damaged?

Accepted Answer

Oligodendrocyte

Question 4

Which of the following best describes the function of the premotor cortex?

Accepted Answer

It is primarily involved in the selection of voluntary movements in response to internal or external stimuli.

Question 5

Which of the following statements about graded potentials is TRUE?

Accepted Answer

Graded potentials can summate and decay over distance.

Question 6

During an action potential, which event occurs immediately after the membrane potential reaches threshold?

Accepted Answer

Voltage-gated sodium channels open, causing rapid depolarization.

Question 7

Which of the following best describes the direction of information flow in a typical neuron?

Accepted Answer

Dendrite → Cell body → Axon

Question 8

Which of the following is a key difference between the autonomic and somatic motor systems?

Accepted Answer

The somatic system always stimulates skeletal muscle, while the autonomic system can stimulate or inhibit target organs.

Question 9

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 10

Which of the following is TRUE regarding the all-or-none principle of action potentials?

Accepted Answer

If threshold is reached, an action potential of fixed size will occur.

Question 11

Which neurotransmitter is released at the neuromuscular junction to stimulate skeletal muscle contraction?

Accepted Answer

Acetylcholine

Question 12

A drug blocks voltage-gated calcium channels at the presynaptic terminal. What is the most likely effect?

Accepted Answer

Decreased release of neurotransmitter into the synaptic cleft

Question 13

Which of the following is a function of ependymal cells in the central nervous system?

Accepted Answer

Lining fluid-filled cavities and helping circulate cerebrospinal fluid

Question 14

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

Accepted Answer

It is the site where action potentials are initiated.

Question 15

Which of the following is a characteristic of the refractory period during an action potential?

Accepted Answer

The neuron cannot generate another action potential, regardless of stimulus strength.

Question 16

Which of the following is TRUE about the propagation of action potentials?

Accepted Answer

They propagate in one direction due to the refractory period.

Question 17

Which of the following best explains why graded potentials decay over distance?

Accepted Answer

They lack voltage-gated channels to sustain the signal.

Question 18

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 into synaptic cleft

Question 19

Which of the following is a function of astrocytes in the central nervous system?

Accepted Answer

Forming the blood-brain barrier and supporting neurons

Question 20

A patient presents with muscle weakness due to impaired neuromuscular transmission. Which of the following is most likely affected?

Accepted Answer

Release of acetylcholine at the synaptic cleft

The Nervous System: Structure and Function

Study Guide - Practice Questions