Question

Describe the process of urine formation in kidneys.

Answer 1

Urine formation in kidneys :- The basic filtration unit in the kidneys is a cluster of very thin-walled blood capillaries. Each capillary cluster in the kidney is associated with the cup-shaped end of a coiled tube called Bowman’s capsule that collects the filtrate. Each kidney has large numbers of these filtration units called nephrons packed close together.

Some substances in the initial filtrate, such as glucose, amino acids, salts and a major amount of water, are selectively reabsorbed as the urine flows along the tube. The amount of water re-absorbed depends on how much excess water is there in the body, and on how much dissolved waste there is to be excreted. The urine forming in each kidney eventually enters a long tube, the ureter, which connects the kidneys with the urinary bladder.

Urine is stored in the urinary bladder until the pressure of the expanded bladder leads to the urge to pass it out through the urethra. The bladder is muscular, so it is under nervous control.