Question 1

Which of the following best describes the difference between nuclei and ganglia in the organization of neurons?

Accepted Answer

Nuclei are clusters of cell bodies in the CNS, while ganglia are clusters of cell bodies in the PNS.

Question 2

A patient suffers from a demyelinating disease affecting the central nervous system. Which type of glial cell is most likely impaired?

Accepted Answer

Oligodendrocytes

Question 3

Which of the following best explains why the resting membrane potential (RMP) of a neuron is close to the equilibrium potential of potassium ($$E_K$$)?

Accepted Answer

The membrane is highly permeable to potassium ions due to leak channels.

Question 4

Which equation would you use to calculate the equilibrium potential for potassium ($$E_K) in a $$neuron, and what does it represent?

Accepted Answer

$$E_K = \frac{RT}{zF} \ln \frac{[K^+]_{out}}{[K^+]_{in}}$$; it represents the membrane potential at which there is no net movement of potassium ions.

Question 5

A neuron is exposed to a toxin that blocks voltage-gated sodium channels. What is the most likely effect on the neuron's ability to generate an action potential?

Accepted Answer

The neuron will be unable to depolarize and generate an action potential.

Question 6

Which of the following best describes the function of the sodium-potassium pump ($$Na^+/K^+-$$ATPase) in maintaining the resting membrane potential?

Accepted Answer

It moves 3 $$Na^+$$ ions out and 2 $$K^+$$ ions in, making the inside of the cell more negative.

Question 7

A patient has a genetic mutation that causes Schwann cells to malfunction. Which of the following symptoms would most likely be observed?

Accepted Answer

Slowed conduction of action potentials in the peripheral nervous system.

Question 8

Which of the following is a property of graded potentials but NOT action potentials?

Accepted Answer

They are decremental and decrease in amplitude with distance.

Question 9

If the extracellular concentration of potassium ($$[K^+]_{out}) $$increases significantly, what will happen to the resting membrane potential of a neuron?

Accepted Answer

The resting membrane potential will become less negative (depolarized).

Question 10

Which type of ion channel is always open and primarily responsible for the resting membrane potential?

Accepted Answer

Leak channels

Question 11

A neuron receives multiple excitatory postsynaptic potentials (EPSPs) from different presynaptic neurons at the same time. What is this process called?

Accepted Answer

Spatial summation

Question 12

Which glial cell type is responsible for forming the blood-brain barrier and providing metabolic support to neurons?

Accepted Answer

Astrocytes

Question 13

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

Accepted Answer

Voltage-gated potassium channels open, allowing $$K^+ to $$exit the cell.

Question 14

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 via saltatory conduction.

Question 15

A patient presents with muscle weakness and loss of reflexes. Laboratory tests reveal antibodies against acetylcholine receptors. Which part of the nervous system is most directly affected?

Accepted Answer

The synapse between motor neurons and skeletal muscle (neuromuscular junction)

Question 16

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

Accepted Answer

They act as immune cells, removing debris and pathogens.

Question 17

If a neuron is at rest and the membrane suddenly becomes more permeable to sodium ions, what will happen to the membrane potential?

Accepted Answer

It will move closer to the equilibrium potential for sodium ($$E_{Na}$$), becoming more positive.

Question 18

Which of the following is a direct effect of the sodium-potassium pump on the resting membrane potential?

Accepted Answer

It creates a net loss of one positive charge from the cell per cycle.

Question 19

A neuron is exposed to a drug that increases the number of open potassium leak channels. What is the most likely effect on the resting membrane potential?

Accepted Answer

The resting membrane potential will become more negative (hyperpolarized).

Organization and Physiology of Neurons: Structure, Function, and Signaling

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