Question 1

Which structure on a neuron is primarily responsible for receiving incoming signals from other neurons?

Accepted Answer

Dendrites

Question 2

What is the main function of the myelin sheath in neurons?

Accepted Answer

To insulate the axon and speed up action potential conduction

Question 3

During the resting membrane potential, which ion has a higher concentration outside the neuron compared to inside?

Accepted Answer

Sodium ($$Na^+)$$

Question 4

Which equation best represents the calculation of the resting membrane potential based on ion concentrations?

Accepted Answer

$$E_{m} = [K^+]_{outside} - [Na^+]_{inside}$$

Question 5

What is the role of the sodium-potassium pump ($$Na^+/K^+$$ ATPase) in neurons?

Accepted Answer

It actively moves $$3\ Na^+$$ out and $$2\ K^+ in $$per ATP to restore the resting potential

Question 6

Which phase of the action potential is characterized by $$Na^+$$ ions moving into the neuron, causing the membrane potential to become more positive?

Accepted Answer

Depolarization (Rising phase)

Question 7

If a patient has multiple sclerosis (MS), which part of the neuron is primarily damaged, and what is the consequence?

Accepted Answer

Myelin sheath; slower and less efficient action potential propagation

Question 8

Which event triggers the opening of voltage-gated $$Na^+$$ channels at the axon hillock?

Accepted Answer

A stimulus that raises the membrane potential to threshold

Question 9

Why does muscle fatigue sometimes result in sodium-potassium pumps leaving ions in the 'wrong' place?

Accepted Answer

Not enough ATP is available to power the pumps

Question 10

Which of the following best describes the propagation of an action potential along a myelinated axon?

Accepted Answer

Action potential 'hops' from one node of Ranvier to the next

Question 11

During the repolarization phase of an action potential, which ion moves out of the neuron?

Accepted Answer

$$K^+$$

Question 12

Which cell type is responsible for producing the myelin sheath in the peripheral nervous system?

Accepted Answer

Schwann cells

Question 13

A neuron is unable to fire another action potential immediately after one has occurred. This period is called:

Accepted Answer

Refractory period

Question 14

Which of the following best explains why the inside of a neuron is negatively charged at rest?

Accepted Answer

The sodium-potassium pump moves more positive ions out than in

Question 15

Which part of the neuron initiates the action potential if the stimulus is strong enough?

Accepted Answer

Axon hillock

Question 16

What would happen if voltage-gated $$Na^+$$ channels failed to open during stimulation?

Accepted Answer

No action potential would be generated

Question 17

Which of the following is TRUE about the direction of action potential propagation in a neuron?

Accepted Answer

It travels from the axon hillock toward the axon terminals

Question 18

Which of the following best describes the function of dendrites?

Accepted Answer

Receive incoming messages and direct them toward the cell body

Question 19

A patient is experiencing slower nerve conduction due to demyelination. Which disease is most likely responsible?

Accepted Answer

Multiple sclerosis (MS)

Question 20

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

Accepted Answer

Depolarization → Peak → Repolarization → Recovery

Neurons and Action Potentials: Structure, Function, and Signal Transmission

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