Question 1

Which of the following best describes the main functional difference between the somatic and autonomic nervous systems?

Accepted Answer

The somatic nervous system allows conscious control of skeletal muscle, while the autonomic nervous system regulates involuntary activities such as heart rate and digestion.

Question 2

A patient is experiencing increased heart rate, rapid breathing, and decreased digestive activity after a car accident. Which division of the nervous system is primarily responsible for these responses?

Accepted Answer

Sympathetic division of the autonomic nervous system

Question 3

Which of the following structures is the site where an action potential is typically initiated in a neuron?

Accepted Answer

Axon hillock/initial segment

Question 4

Which glial cell is responsible for forming the myelin sheath in the central nervous system (CNS)?

Accepted Answer

Oligodendrocyte

Question 5

A researcher is studying the movement of sodium ions across a neuron's membrane. At what membrane potential would the net movement of sodium ions stop, and what is this value called?

Accepted Answer

At $$+60\ \mathrm{mV}$$, called the equilibrium potential for sodium

Question 6

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

Accepted Answer

Myelin allows action potentials to jump between nodes of Ranvier, a process called saltatory conduction.

Question 7

Which of the following is a correct pairing of nervous system terminology and its definition?

Accepted Answer

Tracts: bundles of axons in the CNS

Question 8

A person touches a hot stove and quickly withdraws their hand. Which type of neuron is responsible for carrying the pain signal from the hand to the spinal cord?

Accepted Answer

Sensory (afferent) neuron

Question 9

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

Accepted Answer

They support neurons, help form the blood-brain barrier, and regulate nutrients and ion balance.

Question 10

Which of the following scenarios best illustrates spatial summation in a neuron?

Accepted Answer

Multiple graded potentials from different locations on the neuron combine to reach threshold.

Question 11

Which of the following statements about graded potentials is TRUE?

Accepted Answer

Graded potentials can be either depolarizing or hyperpolarizing and decrease with distance from the stimulus.

Question 12

A neuron is exposed to a chemical that binds to its membrane and causes ion channels to open. What type of channel is being activated?

Accepted Answer

Chemically gated channel

Question 13

During which phase of the action potential does potassium ($$K^+) $$rapidly exit the neuron, returning the membrane potential toward its resting value?

Accepted Answer

Repolarization

Question 14

Which of the following best describes the electrochemical gradient for sodium ($$Na^+) in a $$typical neuron at rest?

Accepted Answer

Both the chemical and electrical gradients drive $$Na^+$$ into the cell.

Question 15

A patient has a demyelinating disease affecting the CNS. Which of the following would most likely be impaired?

Accepted Answer

Saltatory conduction along axons

Question 16

Which of the following best explains why the absolute refractory period prevents a second action potential from occurring immediately after the first?

Accepted Answer

Voltage-gated sodium channels are inactivated and cannot reopen until the membrane repolarizes.

Question 17

Which of the following is a correct sequence of events during continuous propagation of an action potential along an unmyelinated axon?

Accepted Answer

Action potential develops at the initial segment, sodium ions spread, graded depolarization brings next segment to threshold, action potential develops in next segment.

Question 18

Which of the following best describes the function of microglia in the CNS?

Accepted Answer

They act as immune cells, removing debris and pathogens.

Question 19

If a graded potential depolarizes the axon hillock to $$-55\ \mathrm{mV}$$, what is the most likely outcome?

Accepted Answer

An action potential will be triggered.

Question 20

Which of the following is TRUE regarding the difference between white matter and gray matter in the CNS?

Accepted Answer

White matter consists mainly of myelinated axons, while gray matter consists mainly of cell bodies, dendrites, and unmyelinated axons.

Nervous Tissue: Structure, Function, and Physiology (BIO 2111 – A&P I, Chapter 11 Study Guide)

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