Role of Other Organs in Excretion

The kidneys are the main organs of excretion, but they are not the only ones. The lungs, the liver and the skin also share the task of clearing waste substances from the body.

Lungs

The lungs are important excretory organs because they get rid of large amounts of carbon dioxide, removing roughly two hundred millilitres of it every minute. Along with this gas they also release a significant quantity of water each day.

Liver

The liver is the largest gland in the body and contributes to excretion through the bile it secretes. Bile carries away a range of substances, including:

• bilirubin and biliverdin (pigments),
• cholesterol,
• broken-down steroid hormones,
• certain vitamins, and
• drugs.

Most of these materials eventually leave the body together with the digestive wastes.

Skin

The skin helps in excretion through two kinds of glands whose secretions carry substances out of the body.

• Sweat glands produce sweat, a watery fluid that contains sodium chloride together with small amounts of urea, lactic acid and similar substances. The chief job of sweat is to cool the body surface, but as it does so it also removes some of these wastes. …