Describe in brief how urine is produced in human body.

Explanation

It mainly takes place in 3 steps:
i] Glomerular filtrate
ii] Selective re-absorption
iii] Tubular secretion.
Urine is formed in the kidneys through filtration of blood. Each kidney consists of large numbers of filtration units called nephrons which filter out the waste products from the blood. Certain substances such as salts, glucose, amino acids and a major amount of water are reabsorbed as the urine flows along the tube of nephron. Urine then enters into ureter and gets stored in the urinary bladder until the pressure of the expanded bladder leads to the urge to pass it out through the urethra.