Question 1

Which of the following best describes the role of Schwann cells in the peripheral nervous system?

Accepted Answer

They wrap around axons to form myelin sheaths, increasing the speed of electrical signal transmission.

Question 2

A patient suffers from a demyelinating disease affecting the CNS. Which cell type is most likely impaired?

Accepted Answer

Oligodendrocytes

Question 3

Which equation correctly represents the Nernst equation for calculating the equilibrium potential ($E_{ion}$) of an ion across a membrane?

Accepted Answer

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

Question 4

During the propagation of an action potential along a myelinated axon, which process allows the signal to travel faster compared to an unmyelinated axon?

Accepted Answer

Saltatory conduction

Question 5

If the resting membrane potential of a neuron is $-70\ \mathrm{mV}$, what happens when sodium channels open and sodium ions enter the cell?

Accepted Answer

The membrane potential becomes less negative, leading to depolarization.

Question 6

Which of the following best explains the 'all-or-none principle' of action potentials?

Accepted Answer

An action potential will only occur if the stimulus is strong enough to reach the threshold; otherwise, no action potential is generated.

Question 7

Which glial cell type is responsible for forming the blood-brain barrier?

Accepted Answer

Astrocytes

Question 8

A patient is unable to move their right arm after a stroke. Which division of the motor system is most likely affected?

Accepted Answer

Somatic motor division

Question 9

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

Accepted Answer

They act as phagocytes, removing debris and pathogens.

Question 10

Which of the following is TRUE regarding the propagation of an action potential?

Accepted Answer

It is propagated by the opening of voltage-gated sodium channels followed by potassium channels.

Question 11

Which equation correctly represents the calculation of membrane potential using the Goldman-Hodgkin-Katz equation?

Accepted Answer

$V_m = \frac{RT}{F} \ln \left( \frac{P_{K^+}[K^+]_{out} + P_{Na^+}[Na^+]_{out} + P_{Cl^-}[Cl^-]_{in}}{P_{K^+}[K^+]_{in} + P_{Na^+}[Na^+]_{in} + P_{Cl^-}[Cl^-]_{out}} \right)$

Question 12

Which of the following scenarios would most likely result in hyperpolarization of a neuron?

Accepted Answer

Efflux of potassium ions ($K^+$) from the neuron

Question 13

Which of the following best describes the function of ependymal cells?

Accepted Answer

They circulate cerebrospinal fluid and line the ventricles of the brain.

Question 14

A patient is experiencing muscle weakness due to impaired signal transmission at the neuromuscular junction. Which neurotransmitter is most likely deficient?

Accepted Answer

Acetylcholine

Question 15

Which of the following is a correct sequence of events during an action potential?

Accepted Answer

Depolarization, repolarization, hyperpolarization

Question 16

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

Accepted Answer

Myelin insulates the axon, allowing action potentials to jump between nodes of Ranvier.

Question 17

Which of the following is TRUE regarding excitatory and inhibitory postsynaptic potentials (EPSP and IPSP)?

Accepted Answer

If EPSPs outnumber IPSPs, an action potential will be triggered.

Question 18

Which of the following best describes the function of interneurons?

Accepted Answer

They connect sensory and motor neurons within the CNS, facilitating integration.

Question 19

Which of the following structures is responsible for integrating information and then sending it along the axon as an action potential?

Accepted Answer

Axon hillock

Introduction to the Nervous System: Structure, Function, and Physiology

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