nefronu

In Polish, the functional unit of the kidney is called nefron, with the genitive form nefronu; in English the term is nephron. The nephron is the basic unit that filters blood, reabsorbs essential substances, and excretes wastes to form urine.

A nephron consists of a renal corpuscle, where filtration begins, and a renal tubule, where the filtrate is processed.

The renal tubule includes the proximal convoluted tubule, loop of Henle, distal convoluted tubule, and collecting duct. Filtration occurs across the glomerular capillaries, while reabsorption and secretion along the tubule adjust solute and water balance.

Blood supply includes the afferent and efferent arterioles feeding the glomerulus, with peritubular capillaries and, in juxtamedullary nephrons, vasa recta supporting reabsorption and concentration of urine.

Most nephrons are cortical, located mainly in the renal cortex; juxtamedullary nephrons extend deeper, contributing to medullary osmotic gradients. Nephron formation begins during fetal development from metanephric mesenchyme interacting with the ureteric bud.

Clinical relevance: nephron loss from injury or disease contributes to chronic kidney disease; preserving nephron function is central to renal health, with therapies targeting blood pressure, glucose control, and hormonal regulation.