Excretory System
Prepared By: Maria Johanna Baguio Testa
Excretory System
Metabolism - refers to all the chemical processes that take place in the body.
- may result in the production of waste products which are often toxic.
The three main purposes of metabolism are:
- the conversion of food to energy
- to run cellular processes
- the conversion of food/fuel
Excretory System
Excretion - is the elimination of the metabolic waste products from the body.
*Note: defecation (pooping) is not excretion because feces contain undigested food which has not been absorbed into the cells or taken part in metabolism.
Example of waste products:
- Carbon dioxide (lungs), urine (kidneys), sweat (skin)
The Importance of Excretion:
- Disposal of toxic or poisonous wastes. For examples, urea and carbon dioxide.
- Disposal of excess substances. For examples, salts and water.
The Main Organs Involved in Excretory System:
Skin - protects our body and acts as an excretory organ. (sweating)
- Sweat glands - produce sweat when the body is hot. Is a long coiled tube.
- Sweat duct- are small tubular structures of the skin that produce sweat
- Sweat pore - is an opening of a sweat gland to the surface of the skin.
- Sweat - is extracted from the blood capillaries surrounding the sweat glands.
- Sweat Contains:
Water
Mineral salts
Urea
Lungs:
During the cellular respiration, the cells produce carbon dioxide and water as a waste products. Carbon dioxide diffuses out of the blood capillaries into the alveoli. Carbon dioxide and water vapor are expelled from the lungs by exhalation.
Kidneys:
Main orgarn of the excretory system.
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