Nephron

functional basic unit of the kidney, consisting of the renal corpuscle (glomerulus) and the urinary tubules (tubules). The primary urine is formed here. Gradually, the final urine is formed in the nephron by the intake of further urinary substances and the withdrawal of substances that the body still needs.

https://de.wikipedia.org/wiki/Nephron _{(Wikipedia CC-by-sa-3.0)}