Question 1

Which of the following best describes the role of the nervous system in maintaining homeostasis?

Accepted Answer

It maintains homeostasis by rapidly responding to stimuli using nerve impulses (action potentials).

Question 2

A patient suffers damage to the axons of neurons in the peripheral nervous system (PNS). Which cell type is most directly involved in the repair process, and why is this possible?

Accepted Answer

Schwann cells, because they form neurolemma which allows for axon regeneration if the cell body is intact.

Question 3

Which of the following correctly matches the neuron type with its location?

Accepted Answer

Bipolar neurons: found in the retina of the eye and inner ear

Question 4

During the depolarizing phase of an action potential, which event occurs first?

Accepted Answer

Voltage-gated Na$$^+$$ channels open rapidly, allowing Na$$^+ to $$enter the neuron.

Question 5

Which equation best represents the electrochemical gradient that drives ion movement during an action potential?

Accepted Answer

$$E_{ion} = \frac{RT}{zF} \ln \left( \frac{[ion]_{out}}{[ion]_{in}} \right)$$

Question 6

A patient is prescribed an SSRI for depression. What is the primary mechanism by which SSRIs affect neurotransmission?

Accepted Answer

They block the reuptake of serotonin, increasing its concentration in the synaptic cleft.

Question 7

Which of the following is TRUE regarding myelination in the CNS versus the PNS?

Accepted Answer

Oligodendrocytes myelinate multiple axons in the CNS, but there is no neurolemma, resulting in poor axon regrowth.

Question 8

Which type of ion channel is primarily responsible for maintaining the resting membrane potential in neurons?

Accepted Answer

Potassium (K$$^+) $$leakage channels

Question 9

A patient with multiple sclerosis (MS) is experiencing muscle weakness and double vision. What is the underlying cause of these symptoms?

Accepted Answer

Progressive destruction of myelin sheaths in the CNS by the immune system, resulting in impaired nerve impulse conduction.

Question 10

Which of the following best explains why saltatory conduction is faster than continuous conduction?

Accepted Answer

Saltatory conduction allows the action potential to 'leap' from node to node, reducing the number of ion channels that must open.

Question 11

Which neuroglia cell type is responsible for producing and circulating cerebrospinal fluid (CSF) in the CNS?

Accepted Answer

Ependymal cells

Question 12

A neuron at rest has a membrane potential of $$-70	ext{mV}. $$What does this value indicate?

Accepted Answer

The inside of the neuron is $$70	ext{mV}$$ more negative than the outside.

Question 13

Which of the following is a correct sequence of events at a chemical synapse?

Accepted Answer

Nerve impulse arrives, Ca$$^{2+}$$ channels open, Ca$$^{2+}$$ influx triggers exocytosis of neurotransmitter, neurotransmitter binds to ligand-gated channels.

Question 14

Which of the following is NOT a function of astrocytes in the CNS?

Accepted Answer

Formation and maintenance of the myelin sheath

Question 15

Which of the following best describes the 'all-or-none' principle of action potential generation?

Accepted Answer

If the stimulus reaches threshold, an action potential of fixed amplitude is generated; if not, no action potential occurs.

Question 16

Which of the following is a plausible consequence of failure to remove neurotransmitter from the synaptic cleft?

Accepted Answer

Continuous, unwanted action potentials are generated in the postsynaptic neuron.

Question 17

Which of the following best explains why neurons in the CNS have limited ability to regenerate after injury?

Accepted Answer

Oligodendrocytes in the CNS do not form neurolemma, which is necessary for axon regeneration.

Question 18

Which type of neuron is most likely to transmit pain sensations and why?

Accepted Answer

C-fibers, because they are small in diameter and unmyelinated, conducting pain impulses slowly.

Nervous Tissue: Structure, Function, and Physiology

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