Electrolytes: Sodium and Potassium

CATIONS

Na⁺ --˃ K⁺ --˃ Ca⁺⁺--˃ Mg⁺⁺

ANIONS

Cl⁻ --˃ HCO₃⁻ --˃ iPO₄⁻ᶾ

Lean

+10% from the calculated body water

Obese

-10% from the calculated body water

Very obese

-20% from the CBW

40-75 %

average water content of the human body (age and obesity)

ECF

1/3 of the total body water (approx.16 L)

ICF

2/3 of total body water (approx.24 L)

60%

body’s water is inside the cells

40%

rest is in the bloodstream or tissue fluids.

Salt content

body is the main determinant of the extracellular volume.

30 liters

fluid passes from the blood to the tissue spaces daily

Normal plasma

93% water + 7% solutes. (glucose, lipids, proteins, NPN, amino acids and ions)

12% higher

Water content of plasma is ____ than that of a whole blood

92% water

Plasma contains

8% water

Whole blood

Edema

Retention of 3 Liters of fluid in the tissue will result to _______

10-20L

Deficiency of vasopressin (ADH) caused _____ of water excreted daily. (regulate blood pressure, blood osmolality, and blood volume)

800ml-2L

urine output

50mmol/Na and 5mmol/K

Sweat contains

Na, Cl, K

For volume and osmotic regulation

K

For myocardial rhythm and contractility

Ca, Mg

necessary for cardiac function

Ca, Mg, Zn

Important cofactors in enzyme activation

Apoenzymes

inactive protein part of an enzyme, which requires a cofactor for its activity

Holoenzymes

active and a complete functional enzyme

Mg

For the regulation of ATPase ion pumps

ATP

provides energy to help/drive Na-K pump. o main energy molecule used by the cells.

Magnesium

• cofactor for the activation of enzymatic ATP hydrolysis

• important in insulin secretion.

• Replication of DNA and the translation of mRNA

K, Ca, Mg

For neuromuscular excitability

Acute hypocalcemia

CNS manifestations, mental status, seizures

Mg and PO4

For the production and use of ATP from glucose

4 molecules ATP

Later steps (refer to glycolysis pathway)

Phosphate-lipid bilayer, G-6-phosphatase

production glucose release into blood

HCO3-, K, Cl

Maintenance of pH (acid base balance)

Normal acid

base balance is maintained by the lungs and kidneys

Acidosis

6.5pH and below

Alkalosis

7.5pH and above

Sodium

Major extracellular cation

Potassium

The major intracellular cation

Chloride

Major extracellular anion (chief counter ion of Sodium in ECF)

Calcium

Present almost exclusively in plasma, Involves in blood coagulation

Inorganic phosphorous

major intracellular anion. Inversely related to calcium. Phosphate is essential for the insulin mediated entry of glucose into cells by a process involving phosphorylation (the attachment of a phosphate group to a molecule or an ion) of the glucose and the co-entry of potassium

Mg

An intracellular cation second in abundance to potassium.

Bicarbonate

The second abundant anion in the ECF.