Question 1

Which of the following best describes the function of oligodendrocytes in the central nervous system (CNS)?

Accepted Answer

They form myelin sheaths around axons, increasing the speed of nerve impulse conduction.

Question 2

A patient is diagnosed with multiple sclerosis (MS), a disease characterized by demyelination in the CNS. Which of the following best explains how demyelination affects nerve impulse transmission?

Accepted Answer

It prevents saltatory conduction, causing slower and less efficient transmission of action potentials.

Question 3

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

Accepted Answer

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

Question 4

During the generation of an action potential, which event occurs immediately after the membrane potential reaches threshold?

Accepted Answer

Voltage-gated sodium channels open, causing rapid depolarization.

Question 5

Which of the following best explains why action potentials only travel in one direction along an axon?

Accepted Answer

The absolute refractory period prevents the membrane behind the action potential from depolarizing again.

Question 6

A neuron receives simultaneous excitatory and inhibitory postsynaptic potentials (EPSPs and IPSPs) at its dendrites. Which process determines whether the neuron will fire an action potential?

Accepted Answer

Spatial summation at the axon hillock integrates all incoming signals.

Question 7

Which of the following is a function of astrocytes in the CNS?

Accepted Answer

Regulating the blood-brain barrier and maintaining the extracellular environment.

Question 8

A patient suffers a spinal cord injury that disrupts the ascending tracts. Which function is most likely to be impaired?

Accepted Answer

Sensory perception from the body to the brain.

Question 9

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

Accepted Answer

It actively transports 3 $$Na^+$$ ions out and 2 $$K^+$$ ions in, maintaining a negative intracellular environment.

Question 10

Which type of neural circuit is characterized by a single input that diverges to activate multiple outputs, such as the withdrawal reflex?

Accepted Answer

Diverging circuit

Question 11

Which of the following neurotransmitters is primarily associated with excitatory synaptic transmission in the CNS?

Accepted Answer

Glutamate

Question 12

A neuron is classified as multipolar. Which of the following best describes its structure?

Accepted Answer

One axon and multiple dendrites

Question 13

Which of the following best explains the effect of myelination on the conduction velocity of action potentials?

Accepted Answer

Myelination increases conduction velocity by enabling saltatory conduction between nodes of Ranvier.

Question 14

Which of the following is TRUE regarding the absolute refractory period of a neuron?

Accepted Answer

No action potential can be generated, regardless of stimulus strength.

Question 15

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

Accepted Answer

They act as immune cells, removing debris and pathogens by phagocytosis.

Question 16

A patient is exposed to a neurotoxin that blocks voltage-gated sodium channels. What is the most likely effect on neuronal function?

Accepted Answer

Action potentials cannot be initiated, leading to loss of neural signaling.

Question 17

Which of the following best describes the process of synaptic transmission at a chemical synapse?

Accepted Answer

Neurotransmitters are released from the presynaptic neuron and bind to receptors on the postsynaptic membrane.

Question 18

Which of the following is a characteristic of graded (local) potentials compared to action potentials?

Accepted Answer

Graded potentials can summate and vary in amplitude depending on stimulus strength.

Question 19

Which of the following best explains the role of the axon hillock in neuronal signaling?

Accepted Answer

It integrates incoming signals and initiates action potentials if threshold is reached.

Question 20

Which of the following best describes the effect of inhibitory neurotransmitters on the postsynaptic membrane?

Accepted Answer

They cause hyperpolarization by opening chloride or potassium channels.

The Nervous System: Nervous Tissue – Structure, Function, and Physiology

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