Digestion
The information brought back here have only an illustrative aim: they are not riferibili neither to prescription neither to medical councils -
digestion it is the process that allow men and animals to gain the substances necessary chemistries to just the maintenance from the elements that encircle them.
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Human anatomy
Generality
Nearly all that that comes ingested needs of digestion, is least the substances that can be assimilated without this process.
All the members of the alimony can be led back three great families:
The molecules of which they are compounds, are too much large so that they can be absorbed from the pori of the mucosa of and intestine and they must be therefore scisse in smaller units.
The job carried out from the digesting channel is just this, to decompose large composed molecules in simpler: , glycerin, fat acids, .
This transformation is rendered thanks to the presence possible in of glands that secernono (or ferments).
Glands of the digesting channel
Every gland is constituted a body to ghiandolare, said adenomero, and from a tubulo escretore that it collects secreto and the door to the outside, escretore scholarly saying.
Various types of glands exist. Simplest they are those mail in , composed from a single layer of cells, arranged along the tubulo, that they assume lengthened shape (tubular simple) or a shape to fiasco (alveolar simple). In some cases the tubulo raggomito it (ramificate gland glands gomitolo) or ramifica (). If in a gland they are present tubuli and ampollari expansions, this comes defined tubulo-alveolar. Finally, if its shape is similar to that one of a grape bunch, it comes said acinosa gland.
It is made of the digestion
The first phase of the digestion happens in mouth: the food must very be chewed, for being able sminuzzato and to be stirred with . The bolus that is created comes swallowed and, passing from, introduced in the stomach.
During the food comes ulteriorly sminuzzato to work of the contractions of the gastric walls, while the gastric juices dilute it.
Contractions of the digesting channel
Not hardly the food has entered in , they begin the peristaltic contractions, than from the region pilorica propagano towards the pilorica valve. At first they are weak people and near the pylorus, they become therefore more frequent and near the median part of the stomach.
In this phase the pylorus remains closed and the food mass that comes capacity lì, will be pushed out to behind, allowing a rimescolamento between the ingested food and gastric juice. When the content of the stomach will have caught up a semifluid consistency, the pilorica valve will open every time that will be caught up from a contraction wave, allowing to chimo to pass through duodenum, where it will endure an ulterior elaboration, thanks to pancreatico juice that it comes supplied from . In the duodenum it meets also bile coming from from the liver.
With continuing of the digestion, the peristaltic waves will be originated more and more up, allowing graduate them emptying of the stomach.
After 3 or 4 hours from the term of the meal the stomach practically will be emptied.
The chimo one pours cosi in the duodenum, first part oftenuous intestine, passing little little, in the others two parts of this: fast andileus. Here it happens the decomposition of the complex substances and their absorption. Abandoned the tenuous intestine, nearly all the having substances values nourishing have been absorbed.
Inintestine crasso (distinguished in blind person, colon and resisted) the single resorption of the water and electrolytes happens practically, with the formation of the semi-solid substance that constitutes I made. These fuoriescono from the rectum throughano.
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