The process of eliminating waste matter from the organs, blood or tissues is known as excretion. This act of discharging bodily wastes can also be termed as elimination, purgation or evacuation though the word used in the question is the most apt word. Excretion is one of the most important processes in life because the waste products like sweat and urine form part of the metabolism that is of no use.
Unicellular or single celled organisms discharge wastes through the cell surface. The higher plants on the other hand discharge unwanted matter like gases through the pores on the surface of the leaves. In humans, the main organs of excretion are the urinary system, lungs and the sweat glands on the skin. While the urinary system comprising of the liver and the kidney expel toxins and urine, the lungs are instrumental in removing water vapour and carbon-dioxide. The skin, the largest organ of the human body, regulates water content in the human body by excreting water and unwanted salt through sweat. Discharge of faeces through the large intestine does not form a part of the excretion process in medical parlance. Apart from ridding the body of toxins and maintaining water content, the process of excretion is an important process of life because it maintains the acid-base balance in the body.
Unicellular or single celled organisms discharge wastes through the cell surface. The higher plants on the other hand discharge unwanted matter like gases through the pores on the surface of the leaves. In humans, the main organs of excretion are the urinary system, lungs and the sweat glands on the skin. While the urinary system comprising of the liver and the kidney expel toxins and urine, the lungs are instrumental in removing water vapour and carbon-dioxide. The skin, the largest organ of the human body, regulates water content in the human body by excreting water and unwanted salt through sweat. Discharge of faeces through the large intestine does not form a part of the excretion process in medical parlance. Apart from ridding the body of toxins and maintaining water content, the process of excretion is an important process of life because it maintains the acid-base balance in the body.