Following are excretory organs in the human body.
(a) Kidney – one pair.
(b) Ureters – One pair
(c) Urinary bladder – One
(d) Urethra – One
In addition to above other excretory organs, other organs are skin, liver, spleen, intestines and lungs which help in excretion.
(a) Kidney: Kidneys are the principal organs of the excretory system. They are bean-shaped and lie on either side of the vertebral column of the abdominal cavity. Kidneys are two in number, dark red in colour and about 10 cm long, 5 cm broad 4 cm thick. On the inner side, there is a depression, through which the ureter runs out to the urinary bladder.
Other excretory organs:
1. Skin: There are numerous small pores on our opening of sweat ducts. The excess of salt and urea along with water diffuse into the sweat glands and escape through the opening of the sweat duct, in the form of perspiration.
2. Liver: Liver converts ammonia into urea. Afterwards, this urea is sent to kidney through blood. Urea is filtered from kidney and discharged in the form of urine.
3. Spleen: The cells of spleen and liver destroy the damaged red blood corpuscles. They make bile pigment from respiratory pigment, which is poured in small intestines along with bile.
4. Intestine: Though intestine does not take an active part in excretion, waste product along with bile juice secreted by the liver and other waste products such as carbonates and phosphates are discharged.
5. Lungs: Carbon dioxide is formed due to oxidation of various food stuff. Blood brings carbon dioxide from different parts of the body to the lungs. This carbon dioxide goes out through nostrils.