6. Sweat, dialysis and excretory products of other animals

Sweat is a substance that is produced on hot summer and humid days. It contains water and some salts. We can see these salts as they form white patches on our clothes, especially in the underarm areas.

 

The evaporation of sweat from our skin, takes up the heat of our body and makes us feel cool during the summer days.

At certain abnormal conditions like injuries and infections, the person's kidneys may stop working. Due to this failure in the working of kidneys waste products begin to accumulate in the blood. This should be filtered artificially as the person cannot survive unless their blood is filtered. This periodical artificial filtration of the blood is known as dialysis.

The methods of waste removal from an organism's body depend on the availability of water. In aquatic animals like fishes, the excretory product is in the form of ammonia which directly dissolves in the water. Inland animals like birds, Snakes and lizards the excretory product is uric acid which is a white semi-solid substance. The primary excretory product in humans is urea.