Membrane Potentials

Question 1

Remember Na⁺ ___, K⁺ ___.

Answer 1

Na⁺ in, K⁺ out

Na⁺ in, K⁺ out

Na⁺ in, K⁺ out

Na⁺ in, K⁺ out

Na⁺ in, K⁺ out

Na⁺ in, K⁺ out

Na⁺ in, K⁺ out

Question 2

Define resting potential (E_f)

Answer 2

The difference/separation of charge across a plasma membrane while a cell is at rest

Question 3

The four requirements for the genesis of a resting potential are

Answer 3

• Presence of nondiffusible anions inside the cell (organelles)
• Selective permeable membrane
• Energy expenditure
• Active transport ions

Question 4

K+ in a cell at rests has an

• _____ chemical gradient and
• ______ electrical gradient

Answer 4

• Outward chemical gradient
• Inward electrical gradient

Question 5

Na+ in a cell at rests has an

_____ chemical gradient and

______ electrical gradient

Answer 5

• Inward chemical gradient
• Inward electrical gradient

Question 6

The depolarization phase of the action potential is _____.

and is caused by _____.

Resulting in _______ potential.

Answer 6

• when the cell becomes less negative/more positive
• Caused by sodium influx
• Decreasing potential

Question 7

The repolarization phase of the action potential is _____.

and is caused by _____.

Resulting in _______ potential.

Answer 7

• When the cell becomes more negative/less positive
• caused by K+ flowing out
• increasing potential

Question 8

The hyperpolarization phase of the action potential is _____.

and is caused by _____.

Resulting in _______ potential.

Answer 8

• more negative than the resting potential
• Excess K+ flow out of the cell
• Increased potential

Question 9

The absolute refractory period is

Answer 9

time interval during which no stimulus can elicit an action potential

Question 10

The relative refractory period is

Answer 10

a period of excitability during which a greater than normal strength of stimulus is required to elicit a cell response