Why do the kidneys filter the blood?

1 Answer
Oct 6, 2016

Kidneys filter blood and in the process remove wastes and excess substances to produce urine.

Explanation:

The functional unit of kidney is the nephron. By the process of ultra filtration, cells , proteins and other large molecules are filtered and returned to the blood.

The left over filterate resembles plasma but is devoid of blood proteins. The composition of this filterate is altered as certain substances are secreted into it and selective reabsorption of water also takes place.
The resulting fluid is called urine.