Action Potential Generation and Propagation Practice Questions

Question 1

Which of the following is/are true about nodes of Ranvier?
1. No myelin
2. Rich in sodium channels

Accepted Answer

Both

Answer

None of the options

Answer

No myelin

Answer

Rich in sodium channels

Question 2

Sequence the events in neuromuscular action potential conduction:
1. Sodium channels open in the end plate
2. Calcium enters at the nerve terminal
3. Release of acetylcholine

Accepted Answer

$2 \rightarrow 3 \rightarrow 1$

Answer

$1 \rightarrow 2 \rightarrow 3$

Answer

$1 \rightarrow 3 \rightarrow 2$

Answer

$3 \rightarrow 2 \rightarrow 1$

Question 3

How many phases are there in the action potential of cardiac muscles?

Accepted Answer

5 phases

Answer

2 phases

Answer

3 phases

Answer

4 phases

Question 4

Duration of maximum contraction depends upon?

Accepted Answer

Absolute refractory period

Answer

Both

Answer

None of the two

Answer

Relative refractory period

Question 5

Which of the following statements about the Na-K pump is false?

Accepted Answer

It is located on the apical membrane of cell

Answer

It is not directly involved in the generation of action potentials.

Answer

It is electrogenic

Answer

It needs ATP for its functioning

Question 6

A patient undergoing a minor surgical procedure is given lignocaine injection. Assertion: Local anaesthetics act by blocking nerve conduction. Reason: Small fibers and non-myelinated fibers are blocked more easily than large myelinated fibers.

Accepted Answer

Both Assertion and Reason are true, and Reason is not the correct explanation for Assertion

Answer

Assertion is false, but Reason is true

Answer

Both Assertion and Reason are true, and Reason is the correct explanation for Assertion

Answer

Assertion is true, but Reason is false

Question 7

Which of the following is true regarding Na+ (sodium) ions?

Accepted Answer

Responsible for depolarization

Answer

Does not help other ions in transport

Answer

Responsible for the resting membrane potential

Answer

Sodium ion is responsible for Donnan effect

Question 8

A patient exhibits hyperkalemia. Which of the following explains how this condition affects nerve excitability?

Accepted Answer

Increases resting membrane potential

Answer

Increases action potential threshold

Answer

Decreases action potential threshold

Answer

Decreases membrane potential

Question 9

Absolute refractoriness of a neuron is due to?

Accepted Answer

Inactivation of Na channels

Answer

Hyperpolarization of Cl channels

Answer

Opening of rectifier K+ channels

Answer

Closure of activated Na channels

Question 10

Which of the following is NOT a characteristic of a biphasic action potential of a mixed nerve?

Accepted Answer

Two or more positive peaks

Answer

Refractory period

Answer

All or none phenomenon

Answer

Recorded on surface

Action Potential Generation and Propagation — MCQs

Action Potential Generation and Propagation — MCQs

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