excretion

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excretion,

process of eliminating from an organism waste products of metabolism and other materials that are of no use. It is an essential process in all forms of life. In one-celled organisms wastes are discharged through the surface of the cell. The higher plants eliminate gases through the stomata, or pores, on the leaf surface. Multicellular animals have special excretory organs. In humans the main organs of excretion are the kidneys and accessory urinary organs, through which urine is eliminated (see urinary systemurinary system,
group of organs of the body concerned with excretion of urine, that is, water and the waste products of metabolism. In humans, the kidneys are two small organs situated near the vertebral column at the small of the back, the left lying somewhat higher than the
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), and the large intestinesintestine,
muscular hoselike portion of the gastrointestinal tract extending from the lower end of the stomach (pylorus) to the anal opening. In humans this fairly narrow (about 1 in./2.
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, from which solid wastes are expelled. The skin and lungs also have excretory functions: The skin eliminates water and salt in sweatsweat
or perspiration,
fluid secreted by the sweat glands of mammalian skin and containing water, salts, and waste products of body metabolism such as urea. The dissolved solid content of sweat is only one eighth that of an equal volume of urine, the body's main
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, and the lungs expel water vapor and carbon dioxide.
The Columbia Electronic Encyclopedia™ Copyright © 2013, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Excretion

 

the freeing of the organism from the end products of metabolism as well as from the foreign substances and excess water, salts, and organic compounds that have entered with food or were formed in the organism. As a result of metabolism, carbon dioxide, certain amino acids, urea, and other substances leave the cell and enter the inter-cellular fluid and then the blood. When excess salts or food substances are consumed or when metabolism is impaired, there is increased concentration of inorganic or organic substances in the blood (for example, glucose and amino acids). The organs of excretion have an important role in keeping constant the composition of the fluids of the internal environment (homeostasis). The process of excretion in vertebrates involves the kidneys, lungs or gills, glands of the gastrointestinal tract, skin, and sweat and salt glands (nasal, rectal). In invertebrates the process involves protonephridia, meta-nephridia, gills, and other organs; in protozoans the excretory organs are the contractile vacuoles. In some animals the products of metabolism and salts are deposited in accumulatory organs or integumentary tissues, which are discarded during molting. Excretion of carbon dioxide and other volatile substances occurs through the lungs or gills. Water, salts, and products of nitrogen metabolism (ammonia, urea, and uric acid) are mainly excreted by the kidneys. Sodium salts are excreted by seabirds and reptiles through the nasal glands and by fish through gills or the rectal gland. A human being weighing 70 kg and eating a normal diet discharges from 10,000 to 20,000 millimoles of carbon dioxide in a 24-hour period through the lungs, while nonvolatile mineral and organic acids and just 1-2 millimoles of bicarbonates are re-moved in the urine. The excretion of water is 1.2 liters in urine, 0.5 liter in sweat, and 0.1 liter in feces. The total quantity of nitrogen excreted in urine is 11 grams, in feces 1.7 grams, and in sweat 1 gram. In a 24-hour period the kidneys discharge 21 grams of urea, 0.63 grams of uric acid, 0.56 grams of hippuric acid, 1.05 grams of creatinine, and 0.78 grams of ammonia.

REFERENCES

Prosser, L., and F. Brown. Sravnitel’naia fiziologiia zhivotnykh. Moscow, 1967. (Translation from English.)

IU. V. NATOCHIN

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

excretion

[ek′skrē·shən]
(physiology)
The removal of unusable or excess material from a cell or a living organism.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
This study was conducted at the Department of Microbiology, Federal Urdu University of Arts, Science and Technology (FUUAST), Gulshan-e-Iqbal campus, Karachi, from February 2015 to March 2016, and comprised samples of soil contaminated with pigeons' excreta. The samples were collected from 20 different places of Karachi reserved for pigeons' feeding.
The total excreta per cage were collected from day 19 to 21 by using trays underneath each cage.
The experimental and basal diets and excreta samples were analyzed for DM (AOAC, 2000), nitrogen content by LECO(r) nitrogen analyzer (model FP-528, Leco Corporation, St.
Table 1 Age group Excreta Disposal: Home in months Mode of onset Normal Diarrhoea Total 0-6 16 02 18 7-12 13 07 20 13-35 34 21 55 36th & above 05 02 07 Total 68 32 100 (20%) Percentage 68 32 100 Age group Excreta Disposal: Outside in months Mode of onset Normal Diarrhoea Total 0-6 00 00 00 7-12 00 00 00 13-35 28 12 40 36th & above 326 34 360 Total 354 46 400 (80%) Percentage 88.5 11.5 100 Diarrhoea Among Children According to Practices of Excreta Disposal: In the present study, majority of the cases, i.e 400(80%) children were defecating outside the household premises whereas in 100(20%) children were defecating somewhere within the household premises.
To be clear, human excreta on its own (minus the synthetic toxins that it becomes mixed with as a result of passing through the same sewers that channel industrial byproducts and the multitudes of other toxic streams that currently define our so-called "modern" society) is a valuable product, quite the opposite of the "waste" moniker that's commonly attached to it.
The GC-MS analysis of methanol extract of the bedbug excreta has shown nine carboxylic acids.
My eardrums are bursting at the sound of shells, my nostrils are filled with obnoxious smells Of human excreta, of death and decay.
The whole of the hills is littered with rubbish and dog excreta, and many trees and hedgerows are festooned with plastic bags of excreta, whilst the buildings, which I believe are listed, are in a state of disrepair and covered in graffiti.
Excreta (spittle) of 10 leafhoppers was collected after they were fed at first on healthy plants, and then additional excreta samples were taken from the same vectors after they had fed on diseased plants.
Manual scavenging refers to the removal of human excreta, also known as night soil, from unsanitary "dry" toilets or toilets without the modern flush system.