Excretion is any process in which excess water or wastes are removed from the body. Excretion is the job of the excretory system. Besides the kidneys, other organs of excretion include the large intestine, liver, skin, and lungs.     The large intestine eliminates solid food wastes that remain after digestion takes place. The liver removes excess amino acids and toxins from the blood. Sweat glands in the skin excrete excess water and salts in sweat. The lungs exhale carbon dioxide and also excess water as water vapor.     The kidneys are the main organs of excretion. Their main function is... Show more

Excretion is any process in which excess water or wastes are removed from the body. Excretion is the job of the excretory system. Besides the kidneys, other organs of excretion include the large intestine, liver, skin, and lungs.    
The large intestine eliminates solid food wastes that remain after digestion takes place. The liver removes excess amino acids and toxins from the blood. Sweat glands in the skin excrete excess water and salts in sweat. The lungs exhale carbon dioxide and also excess water as water vapor.    
The kidneys are the main organs of excretion. Their main function is to filter waste products and excess water from the blood and excrete them from the body as urine. The kidneys help the body maintain homeostasis by filtering all the blood in the body many times each day and producing urine. They control the amount of water and dissolved substances in the blood by excreting more or less of them in urine. The kidneys also secrete hormones that help maintain homeostasis. For example, they produce a hormone that stimulates bone marrow to produce red blood cells when more are needed. They also secrete a hormone that helps regulate blood pressure and keep it within a normal range.    

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