excretion
As elimination ( excretion ) is referred to in the biology and medicine delivery of substances through the path from inside the body to the body surface to the external environment, to remove them from the body. In addition to the external skin , the surface of the body also includes the internal mucous membrane of the digestive tract and the epithelium of the lungs , the gall bladder and the urinary tract . These organs are also known as the excretory organs . The excreted substance, in turn, is also referred to as excretion .
Mechanisms of elimination
Various processes are used for elimination:
- the active excretion of superfluous or toxic substances, see excretion
- defecation
- Urinate
- Vomit
- active breathing
- the passive release of gases by diffusion as part of breathing
If individual substances are excreted in different concentrations, one speaks of fractional excretion .
medicine
Clearance (German excretion ) referred to in medicine the removal of a specific exo- or endogenous substance from an organism. In the case of exogenous substances, clearance is also referred to as elimination .
With renal clearance , the kidneys take over the excretory function, the esophageal clearance cleans the esophagus of gastric contents (including gastric acid ) that have flown back , and the mucociliary clearance removes mucus, bacteria and foreign bodies from the respiratory tract in order to keep the airways free and prevent infections .
The elimination of pathogens is not to be understood as a defense mechanism of the body, but as part of the multiplication strategy of microorganisms or worms . Pathogens can get into the environment through the stool , for example , without the infected person showing symptoms of the disease (asymptomatic excretion). With permanent excretors , this happens over a longer period of time (especially with salmonellosis ).
Differentiation from other terms
Secretion is the discharge of secretions by glands. This process is usually differentiated from excretion. With exocrine secretion , substances are also released ("excreted") on the inner or outer surface of the body, for example sweat or sebum . However, these are not worthless or harmful substances, but are used, for example, for thermoregulation (sweat) or the care of the skin (sebum). In this respect, the exocrine secretion is not a component of the excretion or only in a broader sense.
When breathing, water vapor leaves the lungs together with the air we breathe. This is an undesirable loss of water, the extent of which depends on the humidity of the outside air. When Panting of dogs is not the delivery of water to the end, but the heat dissipation (thermoregulation). These cases of unavoidable water loss cannot be counted as elimination in the sense of the definition.
Other meanings
In metallurgy , precipitation refers to the formation of new phases in a supersaturated metallic alloy and so occurs in the word precipitation hardening .
See also
- Excretory urography is a form of x-ray imaging of the kidneys, ureters, and bladder
- Excretory tuberculosis, a route of transmission of tuberculosis (obsolete term)
Individual evidence
- ^ A b Hans-Hasso Frey, Felix R. Althaus: Textbook of pharmacology and toxicology for veterinary medicine. Georg Thieme, 2007. ISBN 9783830410706 . P. 19f.