Small Intestine

Small Intestine:

 The small intestine is the site where most of the chemical and mechanical digestion is occured. The small intestine absorbs the digested food into the capillaries through villi. Most of the food is digested in Jejunum and Ileum.

The Functions of small intestine

1. The digestion of proteins.
2. Peptides are degraded into amino acids.
3. Lipids (fats) are degraded into fatty acids.
4. Carbohydrates are degraded into the simple sugar.

The three main sections of small intestine are:

• The Duodenum

• The Jejunum

• The Ileum

  The Duodenum:

  It starts from Stomach and ends on Jejunum ligament of Treiz. It is the first and shortest part of small intestine. The bile and pancreatic juice is mix with food in duodenum.
  
  

  The Jejunum:

  The jejunum is a part of small bowel , located between the Duodenum and Ileum. The internal surface of Jejunum, the mucous membrane, is covered in projection called villi,  which increase the surface area of tissues which absorbs the nutrients from the gut contents.
  
  

  The Ileum: 

  It is the last part of small intestine and it connects Jejunum to the large intestine. It absorbs the Vitamin B12 and bile salts. It also have villi on inner surface. The villi contain large number of capillaries.