Question 1

Which of the following best describes the main function of the afferent division of the peripheral nervous system (PNS)?

Accepted Answer

It sends information to the CNS through afferent (sensory) neurons.

Question 2

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

Accepted Answer

Oligodendrocytes

Question 3

A patient presents with symptoms of muscle weakness and sensory disturbances. MRI reveals demyelination in the brain and spinal cord. Which disorder is most likely?

Accepted Answer

Multiple sclerosis (MS)

Question 4

Which equation would you use to calculate the equilibrium potential for a single ion across a neuronal membrane?

Accepted Answer

$$E_{ion} = \frac{61}{z} \log \frac{[ion]_{out}}{[ion]_{in}}$$

Question 5

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

Accepted Answer

Forming myelin sheaths around axons

Question 6

A neuron receives a strong excitatory stimulus that depolarizes the membrane to -50 mV at the axon hillock. What is the most likely outcome?

Accepted Answer

An action potential will be generated and propagated along the axon.

Question 7

Which of the following best explains why action potentials do not lose strength as they travel along the axon?

Accepted Answer

They are regenerated at each segment of the axon by voltage-gated ion channels.

Question 8

Which type of glial cell is primarily responsible for immune defense in the central nervous system?

Accepted Answer

Microglia

Question 9

Which of the following statements about axonal transport is TRUE?

Accepted Answer

Dyneins move materials from the axon terminal to the cell body.

Question 10

A patient has a genetic mutation that affects the function of voltage-gated sodium channels in neurons. Which of the following is a likely consequence?

Accepted Answer

Impaired action potential initiation and propagation

Question 11

Which of the following best describes the role of the enteric nervous system?

Accepted Answer

It acts autonomously or can be controlled by the CNS through the autonomic division of the PNS.

Question 12

Which of the following is a characteristic of graded potentials?

Accepted Answer

They lose strength as they travel through the cell.

Question 13

Which of the following best explains why only a small number of ions need to move across the membrane to change the membrane potential by 100 mV?

Accepted Answer

The concentration gradients for ions are very large compared to the number of ions that move.

Question 14

Which of the following is the correct formula for Ohm’s law as applied to current flow in neurons?

Accepted Answer

$$I = V / R$$

Question 15

Which of the following is a function of ependymal cells in the CNS?

Accepted Answer

Circulating cerebrospinal fluid and possibly serving as a source of neural stem cells

Question 16

A neuron is exposed to a toxin that blocks all voltage-gated potassium channels. What is the most likely effect on the action potential?

Accepted Answer

The neuron will be unable to repolarize efficiently, prolonging the action potential.

Question 17

Which of the following best describes the difference between chemical and electrical synapses?

Accepted Answer

Chemical synapses use neurotransmitters, while electrical synapses use direct cytoplasmic connections.

Question 18

Which of the following is a property of Schwann cells but NOT oligodendrocytes?

Accepted Answer

A single cell wraps a segment of one neuron.

Question 19

Which of the following best describes the role of the trigger zone (axon hillock) in a neuron?

Accepted Answer

It is the region with a high concentration of voltage-gated Na+ channels where action potentials are initiated.

Neurons: Cellular and Network Properties (MOD 3)

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