Expulsion

When excretion is known in biology and medicine, the release of substances on the way from the core to the body surface to the external environment, to remove them from the body. To the body surface are apart from the outer skin and the internal lining of the gut and of the lung epithelium, gall bladder, and the urinary tract. These bodies are also referred to as excretory organs. The precipitated substance in turn is also called excretion.

The release of substances to the body surface can also serve other purposes, such as the care or protection.

An elimination process can various metabolic processes underlying:

• Excretion, a body and organ function, which allows the organism to actively redundant or toxic substances ( waste products ) to get rid of. If individual substances excreted in varying concentrations, it is called a fractional excretion
• Secretion, the secretion of glands secretions by
• The passive diffusion taking place in the form of release of gaseous substances through the lungs
• Germ excretion excretion of pathogens as part of the survival strategy of microorganisms or worms (an agent for their distribution ) asymptomatic shedding: pathogens into (often over the chair) in the environment without the infected person has symptoms of the disease. Dauerausscheider do this over a longer period of time (especially with salmonellosis )

In the case of the digestive tract secretions can be submitted in two opposing ways to the environment: on the one in the direction of digestion in the course of defecation as a bowel movement, on the other hand, contrary to the digestive direction during vomiting.

Deferrals to other concepts

By this definition, it is the water that leaves the lungs with the breath, not an elimination, but an undesirable loss, the extent of which depends on the humidity of the outside air - see also Transpiratio insensibilis.

Sweating in humans and panting in dogs serve only the heat dissipation. Here is accepted for the purpose of thermoregulation ( maintaining body temperature ) the loss of body water.

Likewise, sebum excretion is not, but a body care dienliches secretion of the sebaceous glands, which makes the skin, hair dress and the fletching supple and water repellent.

Other meanings

In metallurgy excretion is a synonym for deposition and thus comes before the word precipitation.