Cell Membrane, Membrane Transport, and Membrane Potential 6

Question 1

What is depolarization?

Answer 1

when the membrane potential becomes less negative than rest

Question 2

What is repolarization?

Answer 2

membrane potential that returns the membrane potential back to rest

Question 3

What is hyperpolarization?

Answer 3

when the membrane potential becomes more negative than resting

Question 4

How are changes in membrane potential defined?

Answer 4

by their initial change in membrane potential

Question 5

What happens when an ion moves down this electrochemical gradient?

Answer 5

the membrane potential moves toward the ion electrochemical gradient

Question 6

What are the determinants of the resting membrane potential?

Answer 6

relative ion permeability and Na/K ATPase activity

Question 7

Is Na or K more permeable at rest?

Answer 7

K

Question 8

How many Na move out and K move in with the sodium potassium pump?

Answer 8

3 Na move out and 2 K move in

Question 9

How do you change the membrane potential?

Answer 9

-change the membrane’s permeability to an ion
-change the ion concentration gradient across the membrane

Question 10

What is hyperkalemia?

Answer 10

increase in blood potassium

Question 11

What happens when there is hyperkalemia?

Answer 11

the K concentration outside the cell is higher than normal, so the electrochemical gradient is smaller
-less K exits the cell and the resting membrane potential is less negative and takes less of a stimulus to cause an action potential