Introduction to Excretion

Excretion is the process by which metabolic waste is removed from the body of an organism. Essentially, metabolic waste can be defined as a harmful product of the metabolic activities taking place in the cell of an organism. The unwanted metabolic waste is called excreta and they are removed by the excretory organs. Initially, an accumulation of metabolic waste slows down metabolic action. If the accumulation is allowed to continue, these reactions can stop altogether.

Waste matter in plants and animals

The table below shows some of the waste products in animals and plants.

Waste in Animals Waste in Plants
Carbon Dioxide Oxygen
Urea Carbon Dioxide
Uric Acid Organic Salts
Water Gums
Excess Salts Resins
Excess Hormones Latex
Excess Bile Alkaloids
Excess Medicines Calcium Oxalate

* Substances in excess, such as salts, are also created from the body.

Remember that egestion is not excretion.

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