Intestine

The information brought back here have only an illustrative aim: not they are riferibili neither to prescription neither to medical councils -

intestine it is the last portion of. It is introduced like a tube to variable bore and from the flexible walls.

Functions of the intestine are

• absorption of the nourishing substances
• and the elimination of the refusal substances (I made).

Human anatomy

It is distinguished the two main parts: and.
The differentiation is due, beyond that for the shape and the length, to the various functions that these carry out.

Tenuous intestine

The tenuous intestine is along 6-8 meters, with a diameter of approximately 3 cm. In this part the digestion of the alimony still happens, with with the absorption of the nourishing. To its inside it is transformed in .

In the tenuous intestine numerous conniventi valves are found, that they increase the surface of the mucosa, necessary for the absorption of nourishing substances. These are to they time covered from internal villas, of the length of approximately 1mm, that they serve anch' they to increase the surface of the mucosa. On the villas they are present microvilli, that they have the same function. In this way the surface of the tenuous intestine is of approximately 250 meters square.

Intestine crasso

The intestine crasso has one length of 1,70 m, with one diameter of 7 cm approximately. Here the absorption by now is reduced to and to it knows them mineral, while he comes carried out the transport of the material not more usable, represented from I made.

These catch up last part of the intestine: , that it finishes with. The ano it is encircled from a muscle (anale sphincter). When this muscle is dilated, I made them come expelled.

It disturbs of the intestine

Comparative anatomy

Salting in the evolutionary scale, one before true internal formation appears in i Metazoi, to leave from i Nemertini. In metazoi inferior the function of intestine the cavity is carried out to gastrovascolare or celenteron.
In , like Annelids, Arthropods, etc., morphologic distinction of the front, medium and posterior begins one intestine in. In the advanced classes ago reply one subdivision of the tube digesting with mechanical in the front feature and ghiandolari functions and of absorption in the others features.
Extension and conformation of the intestine are in relation with the alimentary regimen, to which the structures are connected also that facilitate the absorption of the alimony.
In Urocordati and in i Cefalocordati a respiratory intestine, connected is present to gills.
In i Teleostei fish, in Urodeli and above all in Anuri the internal handles are introduced, than in i resisted them they are generally of uniform bore, while in Birds one appear a lot developed.
In i Mammals it is of present norm a solo (in some Sdenta you of two are present); the intestine in the Mammals is variously convoluto and lengthened, the sistemazione of the colon and its handles, assumes systematic value.

External connections

• The role of the intestine in the digestion
• One section dedicated to the intestine and its problems.
• The several parts of the apparatus digesting, until the tenuous intestine and crasso: description and deepenings.
• Particular images of the tenuous intestine and crasso to the microscope

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