Kidneys are regulatory organs involved in removing wastes from the blood, hormone production, nutrient reabsorption, and regulating electrolyte concentrations, acid-base balance, extracellular fluid volume, and blood pressure. The early proximal tubule is where glucose, amino acids, sodium, chlorine, phosphate, bicarbonate, and water are reabsorbed. Only water is reabsorbed in the thin descending loop of Henle, while sodium, chlorine and potassium are reabsorbed in the thick ascending loop of Henle. Sodium and chlorine are also reabsorbed in the early distal convoluted tubule. Finally, sodium and water are reabsorbed in the collecting tubules. Blood pressure is regulated by the hormones angiotensin II and aldosterone, which increases sodium chloride reabsorption. This results in an expansion of the extracellular fluid compartment, thus increasing blood pressure.

EXAMPLE: Kidney Function References