Practice Set 5A

Question 1

Which of the following contributes to the development of the resting membrane potential in neurons?

Answer 1

K+ is more concentrated in the ICF than in the ECF.

Question 2

Why is sodium more concentrated in the ECF than in the ICF of most neurons?

Answer 2

Sodium is actively pumped out of the cell by transporter proteins.

Question 3

Choose all that are true regarding the Na+-K+ pump.

Answer 3

It helps maintain the proper ion distribution across the membrane, compensating for ion leakage.

It accounts for about 70% of the energy (ATP) required by the nervous system.

Question 4

Choose all of the following statements that are true about signal conduction along unmyelinated fibers.

Answer 4

Unmyelinated fibers have voltage-gated channels along their entire length.

A zone of depolarization excites voltage-gated channels immediately distal to the action potential.

Question 5

Propagation of an action potential down a myelinated axon in which the action potential appears to “jump” from node to node is called __________ conduction.

Answer 5

saltatory

Question 6

Which ion has the greatest influence on the resting membrane potential of most neurons?

Answer 6

Potassium

Question 7

Choose all of the following statements that are true about sodium?

Answer 7

Na+ is about 12 times as concentrated in the ECF as in the ICF.

The resting plasma membrane is much less permeable to Na+ than to K+.