Question

Describe the process of urine formation in kidneys.

Answer 1

Urine formation

1. From the human body, waste is excreted in the form of urine.
2. Urine formation is carried out in three phases:
   • Glomerular filtration
   • Reabsorption
   • Secretion

Steps involved in urine formation in kidneys:

I) Glomerular filtration

1. Glomerulus filtration occurs in the glomerulus.
2. The process occurs across three layers-
   • Epithelium of Bowman's capsule.
   • Endothelium of glomerular blood vessels.
   • The membrane between two layers.

II) Reabsorption

1. Reabsorption is achieved by active and passive transport.
2. 99% filtrate is reabsorbed by the renal tubules.

III) Urine

1. Urine produced- 95% water and 5% nitrogenous wastes.
2. Wastes such as urea, ammonia, and creatinine are excreted in the urine.