Potassium K | Laboratory research

We take 60-100 mmol of potassium (2,34-3,9 g) daily. Almost the same amount is excreted in the urine, about 2% is excreted in the feces and sweat. Potassium taken with food is absorbed in the small intestine and excreted by the kidneys within 24 hours. Even in case of insufficient consumption of potassium-containing foods, 40-50 mcg. Potassium is excreted in the urine daily. Potassium is concentrated mainly in skeletal muscle, liver and myocardium.

With calcium and magnesium K+ Regulates heart contraction and cardiac ejection function.

Potassium and sodium ions are of great importance in the renal regulation of acid-base balance, hydrogen ions and Na in renal tubules.+ And K+ By ion exchange.

Potassium bicarbonate is the major intracellular inorganic buffer. Potassium deficiency develops intracellular acidosis, to which the respiratory centers respond with hyperventilation, leading to pCO2Reduction.

Increases and decreases in serum potassium levels are caused by disturbances in the internal and external potassium balance. External potassium balance is regulated by potassium secretion in the distal and collecting ducts. Renal excretion of potassium and future external balance: potassium intake with food, sodium content and flow rate in distal tubules, acid-base balance, mineralocorticoid function, distal tubular response to mineralocorticoids, anion type and.

Potassium concentration depends on adrenal hormones that stimulate potassium secretion. Mineralocorticoids directly affect potassium secretion in the distal tubules, glucocorticosteroids act indirectly, increasing glomerular filtration rate, urinary excretion, and sodium levels in the distal tubules.

In metabolic or respiratory alkalosis K+ Enters the cells, causing hypokalemia, which is associated with increased urinary potassium excretion due to hyperaldosteronism and an increase in bicarbonate concentrations in the distal tubules.

With inorganic acids (NH4Cl, HCl) induced during acute metabolic acidosis K+ Leaves cell H+ In exchange for and causes acute hyperkalemia; In acidosis caused by organic acids (lactate, ketone bodies), hyperkalemia is secondarily manifested after voluminous exhaustion and a decrease in urination rate.

Changes in potassium metabolism are defined by disturbances in water-salt metabolism and acid-base balance and a characteristic electrocardiogram. Concentrations of potassium in the blood below the level of less than 3,5 mmol / l (hypokalemia) can lead to severe disorders: arrhythmia, muscle weakness, impaired bowel movement, constipation, bloating and increased fatigue. An increase in blood potassium concentration above 5,1 mmol / l (hyperkalemia) is accompanied by cardiac arrhythmia; At very high concentrations of potassium in the blood (up to 12-13 mmol / L), cardiac arrest or respiratory paralysis may develop.

How to prepare for the test?

No specific training is required.

It is recommended to limit alcohol intake, smoking and strenuous physical activity for at least 12 hours before the test.