Skin as Exretory Organ

The skin not only protects our body, but is also an excretory organ. The skin has many sweat glands which produce sweat when the body is hot. Each sweat gland is a long coiled tube. The sweat gland leads to a sweat duct which opens on the skin surface as a sweat pore. Sweat is extracted from the blood capillaries surrounding the sweat glands. Sweat contains water, mineral salt and urea.

Source : http://www.heartspring.net/images/skin_cancer_layers_748.jpg