Parts of the small intestine and their function?

Answer 1

Small intestine consists of three main parts.

1. Duodenum(20-25cm long)
2. jejunum(2.4m long,covers 2/5th of intestine)
3. ileum(lower2/5th os small intestine from jejunum)

Function of Duodenum:

It helps in digestion of food.the acidity of chyme in intestine stimulates the release of secretions from pancreas and liver in duodenum along with the secretions of duodenal cells.

1. pancrease releases pancreatic juice which contains following enzymes,

• Amylopepsin:

it digests starch into maltose

• Lipase:

it hydrolyzes a smalls amount of fats into fatty acid and glycerol.

• Trypsin:

it spilts proteins into peptones and polypeptides.

• presence of NaHCO3:

it neutralizes the acidity of chyme

2.liver secretes bile which is a green watery fluid.It contains no enzymes.It contains BILE SALTS which helps in Emulsification

"Emulsification is the coversion of fatty acids

into diffuseable globular droplets

that can be absorbed onto the blood"

3.Duodenal cells release mucus.

Function Of Jejunum:

The undigested food which escapes from duodenum to jejunum is digested by a group of following enzymes present in jejunum.

• Aminopeptidase:

It converts polypeptides into dipeptides

• Erypsin:

It digest dipeptides into Amino acids

• Maltose:

It digests maltose into glucose.

• Lactase:

It digests lactose into glucoes and galactose.

• Lipase:

coverts fats into fatty acids and glycerol.

Function Of Ileum:All digested food is absorbed by ileum.It contains microscopic Villi which are responsible of assimilation of food.

• All simple sugars and proteins in the form of Amino acids are absorbed by diffusion or active transport into the capillaries via villi.
• Some quantity of fatty acid and glycerol are absorbed in blood capillaries.however,large portion of them enter the epithelial cells of villi,where they recombine into fats.they,then enter into lacteal to form Lipo-protein and enters the blood stream via thoracic lymphatic duct.

Ileocolic Sphincter:

At the end of ileum,there is an ileocolic sphincter that opens and closes at time to allow the enterence of undigested food onto the caecum of large intestine.

Answer 2

Parts of small intestine are duodenum, jejunum and ileum.

Parts of large intestine are caecum, appendix, colon, rectum and anal canal.

Answer 3

Actually 3 parts. Duodenum, Jejunum, Ilieum.

Answer 4

The duodenum, the jejunum, and the ileum.