Lecture 10: Membrane Potential: RMP Graded and (some) Action Potentials

Question 1

Diffusive Force

Answer 1

An unchagred molecule moves passively according to high concentration to low concentration

Question 2

Electromotive Force

Answer 2

Opposites attract, like charges repel

Question 3

Electrochemical gradient

Answer 3

Diffusive + Electromotive Force

Question 4

All cells have a transmembrane potential, Excitable cells can…

Answer 4

Alter its Vm to send and/or recieve signals (potentials)
EX: Neurons and myocytes

Question 5

What channel generates membrane potentials

Answer 5

ion channels

Question 6

Resting membrane potential

Answer 6

-70mv

Question 7

Leak Channels

Answer 7

Always opened
Creates RMP

Question 8

Gated Channels

Answer 8

Most channels open and close depending on ‘gating’ factors

Question 9

How does RMP arise?

Answer 9

From the unequal permeability of ions due to different leak channel abundance

Question 10

Balanced force on an ion

Answer 10

Moves inward and outward at the same rate

Question 11

Equilibrium potential (Eion)

Answer 11

No net movement occurs
Concentration of one ion is exactly balanced by the electrical potential difference across the membrane

Question 12

Equilibrium potential for K+

Answer 12

-90mv

Question 13

Equilibrium potential for Na +

Answer 13

+66mv

Question 14

Net force

Answer 14

Depends on the amount of ions needed to transport membrane potential back to equilibrium potential

Question 15

How are ion concentration differences maintained?

Answer 15

Differences are maintained by active transport

Question 16

Ion pumps

Answer 16

Maintains transmembrane potential
Keep ionic gradients stable
Do not make direct effect on RMP

Question 17

What are signal potentials driven by in excitable membrane?

Answer 17

Driven by the opening and closing of gated ion channels