Navigation Links
Excretion


Excretion is the biological process by which an organism separates waste products from its body. The waste products are then usually expelled from the body by elimination.

In mammals, for example, the two major excretory processes are the formation of urine in the kidneys and the formation of feces in the intestines. The waste products are eliminated by urination and defecation respectively.

While urine and feces are both waste material of body processes, they are in completely different categories. Urine is a waste product of the urinary system process while feces are waste products of the digestive system. Feces may contain about one-third bacteria, most of which are harmless, even beneficial while in the gut, but dangerous to others and they may also contain virulent and even deadly pathogens in the form of bacteria, viruses, amoebae, and various parasitic worms. Urine, on the other hand, contains excess water, salt, and protein waste in the form of urea as uric acid, and seldom any pathogens; should a person be in a situation of insufficient water and in danger of overheating due to lack of persperation, urine may be safely used to dampen clothing to aid cooling. It is futile to attempt to drink it (or salty ocean water), as it requires more water from the body to excrete the salt than is available in the fluid. Some sea birds are able to efficently excrete excess salt through the tear ducts associated with the eyes. Such birds can drink sea water without harm.

In insects, a system involving Malpighian tubules is utilized to excrete metabolic waste. Metabolic waste diffuses or is actively transported into the tubule, which transports the wastes to the intestines. The metabolic waste is then released from the body along with fecal stuffs.

See also


'"/>


(Date:4/17/2017)... MELBOURNE, Florida , April 17, 2017 ... security technology company, announces the filing of its 2016 Annual Report ... Securities and Exchange Commission. ... Report on Form 10-K is available in the Investor Relations section ... well as on the SEC,s website at http://www.sec.gov . ...
(Date:4/11/2017)... -- Research and Markets has announced the addition of ... offering. ... market to grow at a CAGR of 30.37% during the period ... has been prepared based on an in-depth market analysis with inputs ... growth prospects over the coming years. The report also includes a ...
(Date:4/5/2017)... 5, 2017  The Allen Institute for Cell Science ... a one-of-a-kind portal and dynamic digital window into the ... the first application of deep learning to create predictive ... lines and a growing suite of powerful tools. The ... and future publicly available resources created and shared by ...
Breaking Biology News(10 mins):
Other biology definition