Each human body consists of 2 kidneys which comprise 1% of the total body weight. Kidneys are responsible for excretion in the body that is the removal of metabolic waste from the body.
Basic functional and structural unit of the kidneys is known as nephron.
It consists of 2 major structures
- Renal corpuscle
- Renal tubule
Renal corpuscle consists of a bowman's capsule surrounded by clusters of blood capillaries known as glomerulus. Blood enters through a branch of the renal artery and is filtered out in glomerulus. The filtrate moves through the walls of the bowman's capsule and enters the renal tubule.
Renal tubule can be divided into 3 major parts
The first part of renal tubule is PCT (proximal convoluted tubule then comes the 2nd part that is loop of henle and the last part is known as DCT (distal convoluted tubule). Major reabsorption takes place in PCT.
Then comes the last part of nephron, the collecting duct. That is mostly responsible for reabsorption of water. The hormone from hypothalamus ADH (antidiuretic hormone) is responsible for maintaining this water balance. More ADH more reabsorption less ADH less reabsorption.