The microscopic structural and functional unit of the kidney.

The nephrons also function to control blood pressure (via production of renin), red blood cell production (via the hormone erythropoietin), and calcium absorption (via conversion of calcidiol into calcitriol, the active form of vitamin D).

Bowman's capsule - It is a cup-like sac at the beginning of the tubular component of a nephron. A glomerulus is enclosed in the sac. Fluids from blood in the glomerulus are collected in the Bowman's capsule.

Proximal tubule - It is the segment of the nephron in kidneys which begins from the renal pole of the Bowman's capsule to the beginning of loop of Henle .

Loop of Henle - It is the portion of a nephron that leads from the proximal convoluted tubule to the distal convoluted tubule. It helps to concentrate urine in the kidney

Distal tubule - It is a portion of kidney nephron between the loop of Henle and the collecting tubule.

Collection duct system - The collecting duct system is the last part of nephron and participates in electrolyte and fluid balance through reabsorption and excretion, processes regulated by the hormones aldosterone and vasopressin (antidiuretic hormone).