CMB1004/L08 Membrane Potentials

Question 1

Name the 4 regions of neurones.

Answer 1

Dendrites
Cell body
Axon
Axon terminal

Question 2

What does the axon terminal synapse with?

Answer 2

Dendrites of next neurone

Question 3

Name the 2 excitable cells.

Answer 3

Neurones
Muscle cells

Question 4

What is an action potential?

Answer 4

Rapid change in membrane potential

Question 5

What creates resting membrane potential (RMP)?

Answer 5

Unequal distribution of ions

Question 6

What maintains resting membrane potential? (2)

Answer 6

High permeability of membrane to K+
Active transport of Na+ across membrane
Both via membrane proteins

Question 7

How does K+ flow out of the cell?

Answer 7

Through K+ leak channel

Question 8

What is E(Na)?

Answer 8

+60mV

Question 9

What is E(K)?

Answer 9

-86mV

Question 10

What is E(Cl)?

Answer 10

-70mV

Question 11

What is resting membrane potential?

Answer 11

-70mV

Question 12

Why is RMP closer to E(K) than E(Cl) or E(Na)?

Answer 12

K+ is more permeable than Na+ or Cl-

Question 13

Why does membrane potential move closer to E(Na) during action potential?

Answer 13

Brief and rapid switch in permeability

Question 14

Name the 2 membrane proteins that help maintain RMP.

Answer 14

K+ leak channel
Na+/K+ ATPase