Normal values for ion concentrations in and out of the cell

Question 1

Extracellular Concentration of Sodium

Answer 1

140 mM (135 - 145 mM)

Question 2

Extracellular Concentration of Potassium

Answer 2

4 mM (3.5 - 5.0 mM)

Question 3

Extracellular Concentration of Calcium

Answer 3

2.4 mM (2.12 - 2.62 mM), only about half existing as free Ca ions

Question 4

Extracellular Concentration of Chloride

Answer 4

100 mM (95 - 105 mM)

Question 5

Extracellular Concentration of Bicarbonate

Answer 5

25 mM (22 -29 mM)

Question 6

Extracellular Concentration of Hydrogen ions

Answer 6

40 nM, at a pH of 7.4

Question 7

Intracellular Concentration of Sodium

Answer 7

5 - 15 mM

Question 8

Intracellular Concentration of Potassium

Answer 8

140 mM

Question 9

Intracellular Concentration of Calcium

Answer 9

0.1 µM

Question 10

Intracellular Concentration of Chloride

Answer 10

Definitely less than extracellular concentration, but very much dependant on tissue

Question 11

Intracellular Concentration of Bicarbonate

Answer 11

10 - 20 mM, pH dependant

Question 12

Intracellular Concentration of Hydrogen ions

Answer 12

50 -100 nM, at a pH of 7.0 - 7.3