Excretion is the removal of substances from plants, animals and other living organisms. In humans, the skin, lungs and kidneys are excretory organs.
Urine is produced in microscopic structures in the kidney called nephrons. Each kidney contains around a million nephrons.
The Bowman’s capsule (renal capsule):
The first convoluted tubule (proximal convoluted tubule) is responsible for:
The collecting duct is responsible for: