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Encyclopedia > Excretion
The kidneys are important excretory organs in vertebrates.
The kidneys are important excretory organs in vertebrates.

Excretion is the process of eliminating waste products of metabolism and other non-useful materials.[1] It is an essential process in all forms of life. It contrasts secretion, where the substance may have specific tasks after leaving the cell. Image File history File links Download high resolution version (683x900, 217 KB) File links The following pages link to this file: Adrenal gland Wikipedia:Grays Anatomy images with missing articles 23 ... Image File history File links Download high resolution version (683x900, 217 KB) File links The following pages link to this file: Adrenal gland Wikipedia:Grays Anatomy images with missing articles 23 ... Structure of the coenzyme adenosine triphosphate, a central intermediate in energy metabolism. ... Secretion is the process of segregating, elaborating, and releasing chemicals from a cell, or a secreted chemical substance or amount of substance. ...


In single-celled organisms, waste products are discharged directly through the surface of the cell. Multicellular organisms utilize more complex excretory methods. Higher plants eliminate gases through the stomata, or pores, on the surface of leaves. Animals have special excretory organs. A cluster of Escherichia coli bacteria magnified 10,000 times. ... Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell being used to describe the smallest unit of a living organism Cells in culture, stained for keratin (red) and DNA (green) The cell is the... Wild-type Caenorhabditis elegans hermaphrodite stained to highlight the nuclei of all cells Multicellular organisms are organisms consisting of more than one cell, and having differentiated cells that perform specialized functions. ... For other uses, see Plant (disambiguation). ... This is not about surgically created bowel openings; see stoma (medicine) In botany, a stoma (also stomate; plural stomata) is a tiny opening or pore, found mostly on the undersurface of a plant leaf, and used for gas exchange. ...

Contents

Human excretion

In humans, the two major excretory processes are the formation of urine in the kidneys and the formation of carbon dioxide (a human's abundant metabolic waste) molecules as a result y Lucca es un guarrillo que le gusta los travestis. GUARRO!!! Kidneys viewed from behind with spine removed The kidneys are bean-shaped excretory organs in vertebrates. ... Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... Structure of the coenzyme adenosine triphosphate, a central intermediate in energy metabolism. ...


In kidney

Main article: Clearance (medicine)

In humans the main organs of excretion are the kidneys and accessory urinary organs, through which urine is eliminated,[2] and the large intestines, from which solid wastes are expelled in strict biological terminology, the expulsion of feces is not considered to be excretion, since faeces is indigestible food, and not metabolic waste. The skin and lungs also have excretory functions: the skin eliminates water and salts in sweat,[3] and the lungs expel water vapor and carbon dioxide. In medicine, the clearance, also renal clearance or renal plasma clearance (when referring to the function of the kidney), of a substance is the inverse of the time constant that describes its removal rate from the body divided by its volume of distribution (or total body water). ... The kidneys are the organs that filter wastes (such as urea) from the blood and excrete them, along with water, as urine. ... The urinary system is the organ system that produces, stores, and eliminates urine. ... This article is about the urine of animals generally. ... The large intestine, an organ which is now more commonly referred to by its Greek name, the colon, is the last part of the digestive system: the final stage of the alimentary canal in vertebrate animals. ... Horse feces Feces, faeces, or fæces (see spelling differences) is a waste product from an animals digestive tract expelled through the anus (or cloaca) during defecation. ... Rabbit feces are usually 0. ... For other uses, see Skin (disambiguation). ... Human respiratory system The lungs flank the heart and great vessels in the chest cavity. ... This article is about common table salt. ... SWEAT is an OLN/TSN show hosted by Julie Zwillich that aired in 2003-2004. ... Water vapor or water vapour (see spelling differences), also aqueous vapor, is the gas phase of water. ... Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ...


Other

Mucus cells. ... The Respiratory System Among four-legged animals, the respiratory system generally includes tubes, such as the bronchi, used to carry air to the lungs, where gas exchange takes place. ...

Non-human

Chemical structure of uric acid.
Chemical structure of uric acid.

Plants have been shown (by British biologist Brian J. Ford) to translocate wastes into leaves which are then shed. In this fashion, the leaf, in addition to acting as an energy-trapping structure, is also a plant's organ of excretion. Image File history File links File links The following pages link to this file: Uric acid ... Image File history File links File links The following pages link to this file: Uric acid ... Brian J. Ford (born 1939 in Corsham, Wiltshire) is an English independent scientist, prolific author and popular interpreter of scientific issues for the general populace, whose scientific papers and numerous books have been published internationally. ... The leaf is the primary site of photosynthesis in plants. ...


Aquatic animals usually excrete ammonia directly into the external environment, as this compound has high solubility and there is ample water available for dilution. In terrestrial animals ammonia-like compounds are converted into other nitrogenous materials as there is less water in the environment and ammonia itself is toxic. Animal environments are classified as either aquatic (water), terrestrial (land), or amphibious (water and land). ... For other uses, see Ammonia (disambiguation). ... Solubility is a chemical property referring to the ability for a given substance, the solute, to dissolve in a solvent. ... Terrestrial animals are animals that live predominantly or entirely on land, as compared with aquatic animals, which live predominantly or entirely in the water (e. ... Toxic redirects here, but this is also the name of a song by Britney Spears; see Toxic (song) Look up toxic and toxicity in Wiktionary, the free dictionary. ...


Most mammals excrete nitrogenous wastes in the form of urea, an ancestral trait. Subclasses & Infraclasses Subclass †Allotheria* Subclass Prototheria Subclass Theria Infraclass †Trituberculata Infraclass Metatheria Infraclass Eutheria Mammals (class Mammalia) are warm-blooded, vertebrate animals characterized by the presence of sweat glands, including milk producing sweat glands, and by the presence of: hair, three middle ear bones used in hearing, and a neocortex... General Name, symbol, number nitrogen, N, 7 Chemical series nonmetals Group, period, block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... Urea is an organic compound with the chemical formula (NH2)2CO. Urea is also known as carbamide, especially in the recommended International Nonproprietary Names (rINN) in use in Europe. ...


Birds excrete their nitrogenous wastes as uric acid in the form of a paste. This is metabolically more expensive, but allows more efficient water retention and it can be stored more easily in the egg. Many avian species, especially seabirds, can also excrete salt via specialized nasal salt glands, the saline solution leaving through nostrils in the beak. For other uses, see Bird (disambiguation). ... Uric acid (or urate) is an organic compound of carbon, nitrogen, oxygen and hydrogen with the formula C5H4N4O3. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... In most birds and reptiles, an egg (Latin ovum) is the zygote, resulting from fertilization of the ovum. ... The Sooty Tern is highly aerial and marine and will spend years flying at sea without returning to land. ... The beak, bill or rostrum is an external anatomical structure of birds which, in addition to eating, is used for grooming, manipulating objects, killing prey, probing for food, courtship, and feeding their young. ...


Perspiration is another excretory process which removes salts and water, although the primary purpose is cooling. Perspiration (also called sweating or sometimes transpiration) is the production and evaporation of a fluid, consisting primarily of water as well as a smaller amount of sodium chloride (the main constituent of table salt), that is excreted by the sweat glands in the skin of mammals. ...


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. Orders Subclass Apterygota Archaeognatha (bristletails) Thysanura (silverfish) Subclass Pterygota Infraclass Paleoptera (Probably paraphyletic) Ephemeroptera (mayflies) Odonata (dragonflies and damselflies) Infraclass Neoptera Superorder Exopterygota Grylloblattodea (ice-crawlers) Mantophasmatodea (gladiators) Plecoptera (stoneflies) Embioptera (webspinners) Zoraptera (angel insects) Dermaptera (earwigs) Orthoptera (grasshoppers, etc) Phasmatodea (stick insects) Blattodea (cockroaches) Isoptera (termites) Mantodea (mantids) Psocoptera... The Malpighian tubules are the insects main organ of excretion and osmoregulation, helping them to maintain water and electrolyte balance. ... Metabolic wastes or excretes are substances left over from metabolic processes, which cannot be used by the organism (they are surplus or have lethal effect), and must therefore be excreted. ...


Etymology

Many people misuse the term excretion as a euphemism for defecation, and use excrement for feces, but this is medically inexact.[1] Anatomy of the anus and rectum For the death metal band Defecation, see Defecation (band). ... Horse feces Feces, faeces, or fæces (see spelling differences) is a waste product from an animals digestive tract expelled through the anus (or cloaca) during defecation. ...


References

  1. ^ a b Beckett, B. S. (1986). Biology: A Modern Introduction. Oxford University Press, 110. ISBN 0199142602. 
  2. ^ Tigerstedt, Dr. Robert (1906). A Text-book of Human Physiology. D. Appleton and Co., 384-390. 
  3. ^ (Tigerstedt, pg. 395)

See also

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Excretion
Look up excretion in
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Image File history File links Commons-logo. ... Wikipedia does not have an article with this exact name. ... Wiktionary (a portmanteau of wiki and dictionary) is a multilingual, Web-based project to create a free content dictionary, available in over 151 languages. ... Countercurrent exchange is a mechanism used to transfer some component of a fluid from one flowing current of fluid to another across a permeable barrier between them. ... The process of burping, also known as a belching or eructation, is an often audible release through the mouth of gas that has accumulated in the stomach or esophagus. ... Flatulence is the presence of a mixture of gases known as flatus in the digestive tract of mammals expelled from the rectum. ... Homeostasis is the property of either an open system or a closed system, especially a living organism, which regulates its internal environment so as to maintain a stable, constant condition. ... Osmoregulation is the active regulation of the osmotic pressure of bodily fluids to maintain the homeostasis of the bodys water content; that is it keeps the bodys fluids from becoming too dilute or too concentrated. ... In animal physiology, respiration is the transport of oxygen from the ambient air to the tissue cells and the transport of carbon dioxide in the opposite direction. ...

External links

  • Animation of excretion

  Results from FactBites:
 
Excretion: Pharmacokinetics: Merck Manual Professional (643 words)
The biliary system contributes to excretion to the degree that drug is not reabsorbed from the GI tract.
Generally, the contribution of intestine, saliva, sweat, breast milk, and lungs to excretion is small, except for exhalation of volatile anesthetics.
Biliary excretion eliminates substances from the body only to the extent that enterohepatic cycling is incomplete—when some of the secreted drug is not reabsorbed from the intestine.
Studies on PD excretion in camels, llamas and yaks (381 words)
Quantitative aspects of PD excretion in camel were examined in greater details by Guerouali et al.
[77] measured the PD excretion in llamas (Lama glama and L. guanicoe).
The PD excretion was 12-18 mmol/kg DOMI, similar to sheep.
  More results at FactBites »

 
 

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