Describe the structure and functioning of nephrons.

Structure of nephron :
Each nephron is composed of two parts. First one is called Bowman’s capsule.The Bowman’s capsule is a cup-shaped bag at its upper end which contains a bundle of blood capillaries which is called glomerulus. Glomerulus has two parts in which one part is attached to Renal Artery responsible for bringing in the dirty blood(Containing Urea) while the other end comes out of Bowman's Capsule containing the clean blood.

The other part of the nephron is coiled where the substances which are required by the body like sugar (glucose), amino acid, ions and excess water are reabsorbed. The substance remaining in the nephron is mainly urine ,which contains dissolved nitrogenous waste like urea and uric acid, excess salts and water.

Functions of nephron :

• Filtration of blood takes place in Bowman’s capsule from the capillaries of glomerulus.
• Re-absorption : As the filtrate flows along the tubule, useful substances are selectively reabsorbed into the blood by capillaries surrounding the nephron tubule.These substances include glucose, amino acids, salts and water.
• Urine : Urine is remained after reabsorption which contains dissolved nitrogenous waste like urea and uric acid, excess salts and water. Urine is collected from nephrons to carry it to the ureter from where it passes into the urinary bladder.