Metanephros (Gr. Meta — After, Nephros — Kidney)

Metanephros (Gr. Meta - After, Nephros - Kidney)

The metanephros, or secondary kidney, is the permanent kidney of reptiles, birds and mammals.

Metanephros develops from metanephrogenic tissue - a collection of cells located in the posterior part of the intermediate bud of the mesonephros. Nephrons, the functional units of the kidney, are formed from metanephrogenic tissue.

Unlike the primary kidney of the pronephros and the temporary kidney of the mesonephros, the metanephros functions throughout the life of the organism. Metanephros performs important functions - filtering blood, removing metabolic products, maintaining water-salt and acid-base balance.

The development of metanephros begins at a certain stage of embryogenesis and continues after birth. In humans, the final formation of the kidneys occurs by 10-12 years.