Histological Characteristics of Small Intestine::
Like other parts of gastrointestinal tract (alimentary canal) small intestine also consists of serosa and the muscalaris externa muscularis externa consists of smooth muscles arranged in two layers outer layer which is made up of longitudinally running fibres and the inner layer which is made up of circularly running fibres
Submucosa of jejunum shows the presence of glands of brunner These glands are of compound tubular type their secretory portions are chiefly confined to submucosa and their excretory ducts led through muscularis mucosa and get emptyed into crypts of lieberkiin some glands are also found in ileum
Muscularis mucosa (or muscularis interna ) is not a well defined structure as it gets split up by glandular elements
Since ileum performs the function of absorption it shows a number of villi .Villi are minute finger like projecting structures which are present in billions they immensely increase the surface area for the absorption of food A villus is a fold of columnar cells with a lymphatic in its centre called lacteal the lacteal is surrounded by blood vessels it is through these lacteals that the digested food gets absorbed they lymphatics absorb the fat which is carried by the lymphatics the blood vessels absorb carbohydrates and proteins
In addition to villi goblet cells are also present which produce mucous and give protection of the membrane from digestive juices
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