Question

Describe the process of urine formation in kidneys.

Answer 1

• 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 re-absorbed 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 of 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.
• 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.