Question 1

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

Accepted Answer

It actively transports 3 Na+ ions out of the cell and 2 K+ ions into the cell, using ATP.

Question 2

During the depolarization phase of an action potential, which ion moves and in which direction?

Accepted Answer

Na+ moves into the cell.

Question 3

What is the primary cause of the negative charge inside a neuron at rest?

Accepted Answer

Presence of negatively charged anions such as proteins and nucleic acids inside the cell.

Question 4

Which equation can be used to estimate the equilibrium potential for K+ ions across the membrane?

Accepted Answer

The Nernst equation: $$E_K = \frac{RT}{zF} \ln \left( \frac{[K^+]_{outside}}{[K^+]_{inside}} \right)$$

Question 5

Which of the following best explains why myelinated axons conduct action potentials faster than unmyelinated axons?

Accepted Answer

Action potentials are generated only at the nodes of Ranvier, allowing the signal to 'jump' from node to node (saltatory conduction).

Question 6

A patient with multiple sclerosis (MS) is likely to experience which of the following symptoms due to demyelination?

Accepted Answer

Visual disturbances, muscle weakness, and loss of motor control.

Question 7

Which of the following statements about the refractory period is correct?

Accepted Answer

It prevents the backward propagation of the action potential.

Question 8

Which of the following is a characteristic of chemical synapses?

Accepted Answer

They use neurotransmitters to communicate between neurons.

Question 9

What happens to neurotransmitters after they are released into the synaptic cleft?

Accepted Answer

They are broken down by enzymes or reabsorbed by the presynaptic neuron.

Question 10

Which of the following best describes the effect of dopamine loss in Parkinson’s disease?

Accepted Answer

Loss of inhibitory control, resulting in involuntary muscle contractions.

Question 11

During repolarization, which ion channel opens and what is the effect?

Accepted Answer

K+ channels open, causing K+ efflux.

Question 12

Which of the following is true about the distribution of Na+ and K+ ions in a resting neuron?

Accepted Answer

Na+ is more concentrated outside the cell, K+ is more concentrated inside.

Question 13

Which of the following best describes continuous conduction in unmyelinated axons?

Accepted Answer

Action potentials occur at every point along the axon.

Question 14

Which of the following is a real-life application of understanding ligand-gated and voltage-gated channels?

Accepted Answer

Designing drugs that target specific ion channels to treat neurological disorders.

Question 15

If the membrane potential reaches the threshold value, what is the likely outcome?

Accepted Answer

All voltage-gated Na+ channels open, initiating an action potential.

Question 16

Which of the following equations describes the relationship between membrane potential and ion concentrations?

Accepted Answer

The Nernst equation: $$E_{ion} = \frac{RT}{zF} \ln \left( \frac{[ion]_{outside}}{[ion]_{inside}} \right)$$

Question 17

Which of the following is NOT a function of the sodium-potassium pump?

Accepted Answer

Generating action potentials directly.

Question 18

Which of the following neurotransmitters is most directly associated with motor control and is deficient in Parkinson’s disease?

Accepted Answer

Dopamine

Question 19

Which of the following best describes the process of hyperpolarization?

Accepted Answer

Some K+ channels remain open, allowing excessive K+ efflux, making the inside of the membrane more negative than the resting state.

Question 20

Which of the following is a plausible consequence of a malfunctioning sodium-potassium pump in neurons?

Accepted Answer

The neuron would be unable to maintain its resting membrane potential, leading to impaired nerve signaling.

E2 Lecture 4: Nervous System Pt. 2

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