Quiz 1

Question 1

What is the Equilibrium potential of K+?

Answer 1

-90mV

Question 2

What is the Ex of Na+?

Answer 2

+60mV

Question 3

What is the Equilibrium potential of Cl-?

Answer 3

-63mV

Question 4

What is the membrane potential? What does it arise from?

Answer 4

At the resting membrane potential, no ion species is at its equilibrium potential. Membrane potential (Vm) arises from weighted contributions of each ion’s Ex based on:
1. Ion’s concentration gradient
2. Ion’s permeability

Question 5

What is the value of the resting membrane potential?

Answer 5

-70 mV

Question 6

How are electrical signals produced?

Answer 6

Gated channel opens or closes which changes an ion’s membrane permeability and the resting membrane potential.

Question 7

What is depolarizaton?

Answer 7

Vm becomes more positive

Question 8

What is hyperpolarization?

Answer 8

Vm becomes more negative

Question 9

What is repolarization?

Answer 9

Vm returns to original value

Question 10

During electrical signaling, how does permeability and ion concentration change?

Answer 10

Only permeability changes, ion concentrations do NOT change.

Question 11

How do you determine what the Vm needs to be to produce the needed electrical force?

Answer 11

1. Find the direction of chemical gradient
2. Electrical force needs to be the opposite of chemical
3. Determine whether Vm should be positive or negative to push the ion that direction opposite to the chemical gradient.