Small Intestine and Succus Entericus

Small Intestine

Small intestine is the organ of the gastrointestinal tract where most of the absorption of minerals and nutrients from food take place.
  • It is the part of GIT present between the stomach and the small intestine.
  • Length of the small intestine is from 5-9 meter long and smaller than large intestine.
  • Small intestine is the place where maximum chemical and mechanical absorption take place.
  • Small intestine secretes a fluid which contains different types of enzymes, mucus and other inorganic components. 

Parts of Small Intestine

Small intestine is having three parts- Duodenum, jejunum and ileum.

1. Duodenum

Duodenum is the first part of the small intestine where preparation for the absorption of food initiates here.
In duodenum small finger like projections called villi are present that helps in absorption of nutrients from food.

2. Jejunum

Jejunum is the second part of small intestine where enterocytes cells present in the inner lining which absorb the maximum components from the food.

3. Ileum

Ileum is the last part of the small intestine where maximum absorption of the vitamin B12, bile salts, and water take place.


Small intestinal glands are called Crypt of lieberkuhn found in between villi.
The epithelium of small intestine contains different types of cells which performs different functions and helps in the absorption of the food.
  • Enterocytes cells-absorb water and electrolytes.
  • Goblet cells- secreting mucus.
  • Enteroendocrine cells- secreting various hormones.
  • Paneth cells- secreting antimicrobial peptides
  • Stem cells.


Succus Entericus

Fluid secreted by the small intestine is called Succus Entericus. Succus entericus is a pale yellow watery fluid which contains the enzymes- proteolytic, amylolytic and lipolytic enzymes.
These enzymes are peptidase, sucrase, maltase, lactase, and intestinal lipase.
The alkaline secretion produced by the glands present in the small intestine contains the water, mucoproteins and bicarbonates ions.


Composition of the Succus Entericus

Daily up to 3 liters of intestinal juice is produced in the human body in the walls of the duodenum.

composition of Succus Entericus- small intestine juice
(Succus Entericus-small intestine juice)

Succus entericus contains 99.5% water and 0.5% solids.
Solids includes the organic and inorganic substances. 
Organic substances are enzymes and mucus.
Inorganic substances includes the sodium, potassium, calcium, chloride, bicarbonates etc.

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