1. the subjection of a substance to prolonged heat and moisture, so as to soften and disintegrate it.
the act or process of converting food into chemical substances that can be absorbed into the blood and utilized by the body tissue.
Digestion. 1. Carbohydrates: principally starches, lactose, and sucrose. Starches are acted on by the enzyme ptyalin (alpha-amylase) secreted in saliva, by hydrochloric acid (HCl) in the stomach, and by pancreatic amylase and intestinal amylase in the small intestine, which split the starches into maltose and isomaltose. These, in turn, are acted on by maltase and isomaltase and split into two molecules of glucose. Lactose is split by the enzyme lactase into a molecule of galactose and a molecule of glucose. The monosaccharides glucose, galactose, and fructose are absorbed from the small intestine into the blood. 2. Fats: emulsified by bile salts and agitation. The emulsified fats are acted upon by pancreatic and enteric lipase to form fatty acids, glycerol, and monoglycerides, which are absorbed through the intestinal walls. Small quantities of diglycerides and triglycerides are also absorbed. 3. Proteins: acted on chiefly in the stomach by pepsin, which splits proteins into proteoses, peptones, and polypeptides. In the small intestine they are acted on by the pancreatic enzymes trypsin, chymotrypsin, and carboxypeptidase to form polypeptides and amino acids. In the small intestine the peptidases complete the breakdown of the peptides into dipeptides and amino acids. Almost all proteins are eventually digested and absorbed either as amino acids or as dipeptides or tripeptides.
See illustration. Digestion is accomplished by physically breaking down, churning, diluting, and dissolving the food substances, and also by splitting them chemically into simpler compounds. Carbohydrates are eventually broken down to monosaccharides (simple sugars); proteins are broken down into amino acids; and fats are absorbed as fatty acids and glycerol (glycerin). The digestive process takes place in the alimentary canal or digestive system
. The salivary glands, liver, gallbladder, and pancreas are located outside the alimentary canal, but they are considered accessory organs of digestion because their secretions provide essential enzymes.
gastric digestion digestion by the action of gastric juice.
in the omaha system
, a client problem
defined as converting food into substances suitable for absorption and assimilation into the body and supplying water to maintain adequate body fluids.
intestinal digestion digestion by the action of intestinal juices.
pancreatic digestion digestion by the action of pancreatic juice.
primary digestion digestion occurring in the gastrointestinal tract.
salivary digestion the change of starch into maltose by the saliva.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
di·ges·tion (di-jes'chŭn, dī-),
1. The process of making a digest.
2. The mechanical, chemical, and enzymatic process whereby ingested food is converted into material suitable for assimilation for synthesis of tissues or liberation of energy.
[L. digestio. See digest]
Farlex Partner Medical Dictionary © Farlex 2012
digestion (dī-jĕs′chən, dĭ-)
a. The process by which food is converted into substances that can be absorbed and assimilated by a living organism. In most animals it is accomplished in the digestive tract by the mechanical and enzymatic breakdown of foods into simpler chemical compounds.
b. The ability to digest food.
2. Biochemistry The process of decomposing complex organic substances into simpler substances, as by the action of enzymes or bacteria.
3. Chemistry The process of softening or disintegrating by means of chemical action, heat, or moisture.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.
The mechanical, chemical, and enzymatic process whereby ingested food is converted into material suitable for assimilation for synthesis of tissues or liberation of energy.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
digestion The conversion of food into a form suitable for absorption and use by the body. This involves both mechanical reduction to a finer consistency and chemical breakdown to simpler substances.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005
digestion a process in which food is broken down into a form that can be utilized. It usually consists of two elements:
- a mechanical/physical stage, e.g. mastication, churning, emulsification, in which no chemical bonds are broken and no enzymes are required; and
- a chemical stage requiring enzymes in which complex food molecules are broken down by HYDROLYSIS into a state in which they can be absorbed. In most heterotrophic organisms digestion is ‘extracellular’, the enzymes being released outside the cell and the digested products absorbed. In organisms such as the fungi, digestion takes place in the external environment, but in the majority of HETEROTROPHS digestion takes place in a specialized cavity or internal tube, the ALIMENTARY CANAL, which is usually muscular, with food being squeezed through the DIGESTIVE SYSTEM by a process of PERISTALSIS. Primitive animals carry out intracellular digestion, food particles being taken into food vacuoles within the cell and digested there.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005
The mechanical, chemical, and enzymatic process in which food is converted into the materials suitable for use by the body.
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.
Mechanical, chemical, and enzymatic process whereby ingested food is converted into material suitable for assimilation for synthesis of tissues.
Medical Dictionary for the Dental Professions © Farlex 2012
Patient discussion about digestion
Q. My aunt suffered from digestive disorder a few months back. My aunt suffered from digestive disorder a few months back. First we were told that this symptom reveal that she is suffering from fibromyalgia. Later another doctor diagnosed her and said that she is not affected by fibromyalgia. So we like to know actually what is fibromyalgia sometimes mistaken for?
A. I have received similar questions from many of my friends so you are not the first person to have such question, so don’t worry. Usually fibromyalgia is initially mistaken for several other conditions, including Lyme disease, lupus, depression and rheumatoid arthritis to name just a few illnesses. Other conditions for which fibromyalgia is occasionally mistaken include digestive disorders, sleep disorders and thyroid problems. Often, it is because the various symptoms of fibromyalgia are so similar to the symptoms of other disorders that many FMS patients do not receive a proper diagnosis for many years. And this is also why it is especially critical to be seen by either a rheumatologist or a pain specialist to ensure a proper diagnosis, and to rule out other conditions.
Q. It feels like I cannot breath properly, my chest feels heavy and Whenever i eats something it gets even more. If i don't eat much i get gases problem. I am regularly having constipation if i don't take proper medicine. Mostly i have been diagnosed as Digestive System problem, stomach problem, dryness in body and no Problem with my breathing system just cause of gases which causes my chest to remain heavy. I am worried because i never gets my real power in breathing and my digestive system is not getting well. Kindly suggest.
A. I take milk regularly have no problem with it nor with any specific food or i have never tried to look at this aspect. However i do feel stomach problem with foods heavy for stomach like burger or too much oily things..
Q. What is the connection between Acid Reflux and Autism? I heard about a digestive issue called Acid reflux. Some people say that this is related to Autism. What is the connection between Acid Reflux and Autism?More discussions about digestion
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