Q: Which equation correctly represents the calculation of membrane potential ($$V_m) $$using the Nernst equation for a single ion?

$$V_m = \frac{RT}{zF} \ln \left( \frac{[\text{Ion}]_{\text{outside}}}{[\text{Ion}]_{\text{inside}}} \right)$$

Question 1

Which of the following best describes the function of the sodium-potassium pump in maintaining the resting membrane potential of a neuron?

Accepted Answer

It actively transports $$3$$ sodium ions out of the cell and $$2$$ potassium ions into the cell, maintaining a negative membrane potential.

Question 2

A patient presents with demyelination of axons in the central nervous system. Which neuroglial cell is most likely affected, and what is the consequence for action potential propagation?

Accepted Answer

Oligodendrocytes; slower action potential propagation due to loss of myelin.

Question 3

Which of the following best explains why action potentials are self-propagating and do not diminish in strength as they travel along an axon?

Accepted Answer

Voltage-gated sodium channels open sequentially along the axon, regenerating the action potential at each segment.

Question 4

A neuron receives multiple excitatory postsynaptic potentials (EPSPs) in rapid succession from a single presynaptic neuron. Which process is occurring?

Accepted Answer

Temporal summation

Question 5

Which equation correctly represents the calculation of membrane potential ($$V_m) $$using the Nernst equation for a single ion?

Accepted Answer

$$V_m = \frac{RT}{zF} \ln \left( \frac{[	ext{Ion}]_{	ext{outside}}}{[	ext{Ion}]_{	ext{inside}}} ight)$$

Question 6

During the absolute refractory period, which of the following best describes the state of the voltage-gated sodium channels?

Accepted Answer

Activation gates are open and inactivation gates are closed, preventing another action potential.

Question 7

Which neurotransmitter is most likely to be released at the neuromuscular junction and binds to ionotropic receptors to initiate muscle contraction?

Accepted Answer

Acetylcholine

Question 8

A neuron in the dorsal root ganglion is classified as which type of neuron based on its structure?

Accepted Answer

Pseudounipolar neuron

Question 9

Which of the following best describes the difference between white matter and gray matter in the central nervous system?

Accepted Answer

White matter consists mainly of myelinated axons, while gray matter contains neuron cell bodies and unmyelinated axons.

Question 10

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

Accepted Answer

Opening of ligand-gated potassium channels

Question 11

A patient is experiencing symptoms of Parkinson’s disease, which is associated with decreased levels of which neurotransmitter in the basal ganglia?

Accepted Answer

Dopamine

Question 12

Which glial cell is responsible for forming the blood-brain barrier and regulating the extracellular environment in the CNS?

Accepted Answer

Astrocyte

Question 13

Which of the following best describes saltatory conduction in myelinated axons?

Accepted Answer

Action potentials jump from one node of Ranvier to the next, increasing conduction speed.

Question 14

Which neurotransmitter is classified as a biogenic amine and is involved in mood regulation, sleep, and appetite?

Accepted Answer

Serotonin

Question 15

Which of the following is a function of microglia in the central nervous system?

Accepted Answer

Phagocytosis of pathogens and debris

Question 16

A neuron receives both excitatory and inhibitory inputs from multiple presynaptic neurons. Which process determines whether an action potential will be generated?

Accepted Answer

Summation

Question 17

Which of the following best describes the role of the axon hillock in a neuron?

Accepted Answer

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

Question 18

Which of the following is true regarding ligand-gated ion channels?

Accepted Answer

They open when a specific chemical binds to the receptor.

Question 19

Which process is responsible for terminating synaptic transmission by removing neurotransmitters from the synaptic cleft via transporter proteins?

Accepted Answer

Reuptake

Question 20

A patient suffers a spinal cord injury that disrupts the motor (efferent) division. Which of the following would most likely be affected?

Accepted Answer

Voluntary movement of skeletal muscles

Neurophysiology: Vocabulary and Functional Overview

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