M&R 2 (Resting cell membrane + Electrical excitability)

Question 1

What is the concentration of Na+ in the ICF and ECF?

Answer 1

ICF = 10 mM
ECF = 145 mM

Question 2

What is the concentration of K+ in the ICF and ECF?

Answer 2

ICF = 160 mM
ECF = 4.5 mM

Question 3

What is the concentration of Cl- in the ICF and ECF?

Answer 3

ICF = 3 mM
ECF = 120 mM

Question 4

What is the concentration of anions in the ICF and ECF?

Answer 4

ICF = 167 mM
ECF = 40 mM

Question 5

Define the resting membrane potential:

Answer 5

Difference in electrical potential between the inside and outside of a cell (expressed as potential inside relative to outside, as ECM = 0 mV).
Arises due to increased permeability to K+ at rest

Question 6

What is the potential of the extracellular matrix?

Answer 6

0 mV

Question 7

What is the equilibrium potential of K+?

Answer 7

-95 mV

Question 8

What is the equilibrium potential of Na+?

Answer 8

+70 mV

Question 9

What is the equilibrium potential of Ca2+?

Answer 9

+122 mV

Question 10

What is the equilibrium potential of Cl-?

Answer 10

-85 mV

Question 11

Will the opening of K+ or Cl- channels cause hyperpolarisation or depolarisation of the cell?

Answer 11

Hyperpolarisation

Question 12

Will the opening of Na+ or Ca2+ channels cause hyperpolarisation or depolarisation of the cell?

Answer 12

Depolarisation

Question 13

Define the equilibrium potential of an ion:

Answer 13

The membrane potential when the electrical and diffusional forces balance = no net movement of that ion.