Question 1

Which of the following best describes the role of potassium (K+) in establishing the resting membrane potential of a neuron?

Accepted Answer

K+ diffuses out of the cell through leakage channels, making the inside more negative.

Question 2

During the depolarization phase of an action potential, which ion is primarily responsible for the rapid change in membrane potential?

Accepted Answer

Na+ enters the cell through voltage-gated channels, causing the membrane potential to become more positive.

Question 3

What is the typical value of the resting membrane potential in a neuron, and how is it measured?

Accepted Answer

Approximately -70 mV, measured with a microelectrode inside the cell and a ground electrode outside.

Question 4

Which equation best represents the Nernst equation for calculating the equilibrium potential for potassium ($$E_{K^+}) $$across the membrane?

Accepted Answer

$$E_{K^+} = \frac{RT}{zF} \ln \left( \frac{[K^+]_{outside}}{[K^+]_{inside}} \right)$$

Question 5

Which of the following statements about graded potentials is TRUE?

Accepted Answer

Graded potentials are short-distance signals that decay as they spread from the site of stimulation.

Question 6

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

Accepted Answer

An action potential is only generated if depolarization reaches threshold; it either happens completely or not at all.

Question 7

During the repolarization phase of an action potential, what is the primary event occurring at the membrane?

Accepted Answer

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

Question 8

Which of the following is a consequence of the absolute refractory period in neurons?

Accepted Answer

Neurons cannot trigger another action potential regardless of stimulus strength.

Question 9

Which clinical condition is characterized by destruction of myelin sheaths in the CNS, leading to slowed or ceased impulse conduction?

Accepted Answer

Multiple sclerosis

Question 10

Which of the following best describes the function of chemical synapses?

Accepted Answer

They ensure unidirectional communication between neurons through the release and reception of neurotransmitters.

Question 11

Which neurotransmitter is released at neuromuscular junctions and degraded by acetylcholinesterase?

Accepted Answer

Acetylcholine

Question 12

What is the effect of local anesthetics on nerve impulse conduction?

Accepted Answer

They block voltage-gated Na+ channels, preventing depolarization.

Question 13

Which of the following best describes the difference between EPSPs and IPSPs at a chemical synapse?

Accepted Answer

EPSPs cause depolarization, while IPSPs cause hyperpolarization.

Question 14

Which of the following factors increases the rate of action potential propagation along an axon?

Accepted Answer

Larger axon diameter and increased myelination

Question 15

Which equation best represents Ohm's Law as applied to the flow of ions across a neuronal membrane?

Accepted Answer

$$I = \frac{V}{R}$$

Question 16

A patient presents with numbness in their fingers after exposure to cold. Which physiological mechanism best explains this symptom?

Accepted Answer

Cold interrupts blood circulation and delivery of oxygen to neurons, temporarily blocking nerve impulse conduction.

Question 17

Which of the following is TRUE regarding the propagation of action potentials in myelinated versus nonmyelinated axons?

Accepted Answer

Action potentials propagate faster in myelinated axons due to saltatory conduction.

Question 18

Which neurotransmitter is associated with mood regulation, sleep-wake cycles, and is synthesized from tryptophan?

Accepted Answer

Serotonin

Question 19

Which drug can rapidly reverse opioid overdose by blocking opiate receptors, restoring breathing within minutes?

Accepted Answer

Naloxone

Question 20

A neuron receives a strong stimulus, resulting in a high frequency of action potentials. How does the CNS interpret this?

Accepted Answer

As a strong stimulus due to the high frequency of impulses per second.

Fundamentals of the Nervous System and Nervous Tissue: Study Guide

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