Absorption in the Small Intestine is discussed in this article. We hope you find it informative and able to satisfy your research needs.
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The main purpose of the processes taking place in the alimentary canal is to make food easy to absorb. Before foods can be absorbed, they have to be made soluble.
The processes described above have to be made soluble. The process of absorption changes food nutrients into soluble forms.
The nutrients then have to be absorbed, which means it is transferred to the blood and lymph of the circulatory system through the lining of the digestive tract.
Most of the absorption takes place in the small intestine which is in line with a membrane arranged in transverse folds. The intestine has a large surface in contact with the food passing along it.
The lining is covered with finger-like projections called villi, each about 1.25mm long and containing a lymph vessel surrounded by a network of capillaries.
The total surface area of the small intestine is very large. It is richly supplied with blood vessels. The liquid food in the intestine is in contact with the large area of blood vessels and diffuses through the walls into the blood which transports it to the various parts of the body.
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Some of the soluble nutrients are absorbed into the lymph vessel and passed into the lymphatic system and to the tissues. Some are absorbed by the blood in the capillaries and are emptied into the portal vein which carries them directly to the liver.
How Absorption Takes Place:
1. Absorption of end-products of carbohydrate digestion is simple sugars
Most of these are absorbed directly into the blood in the capillaries and are carried by the portal vein to the liver. Here, those not needed for energy may be converted to glycogen.
2. Absorption of end-products of fat digestion
The processes involved in the absorption of fat are not fully understood yet.
Some of the fatty acids pass from the intestine into the intestinal wall and through the lymph vessels to the bloodstream and thence to the tissues.
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3. Absorption of end-products of protein digestion
The amino acids are absorbed from the intestinal tract into the capillaries and pass through the portal vein to the liver.
From here they are carried by the blood to the tissues, where the required proportions of amino acids are removed from the blood and, as needed, are used in protein metabolism.
4. Absorption of other nutrients
Minerals and vitamins are absorbed from the intestine. Water may be absorbed from the stomach, the small, and also the intestine.
The absorbed food is delivered by the circulatory system to every cell in the body and the dissolved food enters the cells. This transportation of the absorbed food to the interior of the body cells.
In conclusion, once the food has been procured, prepared, and presented, it then has to be assimilated by the body. Physical processes break down the food into small particles, chemical processes break down the larger molecules into smaller ones.
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This process changes insoluble forms to soluble forms, breaks down large molecules into smaller ones, changes colloidal forms into crystalline forms, and presents the body with the ultimate building stones and fuel for energy.