See Also

Small intestine

In biology Biology

Biology is the branch of science [i] dealing with the study of life [i]. ... 

 the small intestine Intestine

In anatomy [i], the intestine is the portion of the alimentary canal [i] extendin ... 

 is the part of the gastrointestinal tract Gastrointestinal tract

The gastrointestinal tract or digestive tract, also referred to as the GI tract or the al... 

 between the stomach Stomach

In anatomy [i], the stomach is an organ [i] in the gastrointestinal tract [i] used to digest [i] ... 

 and the large intestine. In human Human

Humans, or human beings, are biped [i]al primate [i]s belonging to the mammal [i]ian species ... 

s over 5 years old it is 17 to 21 feet long. It is divided into three structural parts: duodenum, jejunum Jejunum

In anatomy [i] of the digestive system [i], the jejunum is the central of the three divisions of the small intestine [i] ... 

 and ileum Ileum

In anatomy [i] of the digestive system [i], the ileum is the final section of the small intestine [i]. ... 

. Food from the stomach is allowed into the duodenum by a muscle called the pylorus, or pyloric sphincter, and is then pushed through the small intestine by a process of muscular contractions called peristalsis Peristalsis

In the digestive tract, the muscularis externa propels the material along the alimentary canal.... 

. The small intestine is the site where most of the nutrients from ingested food are absorbed.

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In biology Biology

Biology is the branch of science [i] dealing with the study of life [i]. ... 

 the small intestine Intestine

In anatomy [i], the intestine is the portion of the alimentary canal [i] extendin ... 

is the part of the gastrointestinal tract Gastrointestinal tract

The gastrointestinal tract or digestive tract, also referred to as the GI tract or the al... 

 between the stomach Stomach

In anatomy [i], the stomach is an organ [i] in the gastrointestinal tract [i] used to digest [i] ... 

 and the large intestine. In human Human

Humans, or human beings, are biped [i]al primate [i]s belonging to the mammal [i]ian species ... 

s over 5 years old it is 17 to 21 feet long. It is divided into three structural parts: duodenum, jejunum Jejunum

In anatomy [i] of the digestive system [i], the jejunum is the central of the three divisions of the small intestine [i] ... 

 and ileum Ileum

In anatomy [i] of the digestive system [i], the ileum is the final section of the small intestine [i]. ... 

. Food from the stomach is allowed into the duodenum by a muscle called the pylorus, or pyloric sphincter, and is then pushed through the small intestine by a process of muscular contractions called peristalsis Peristalsis

In the digestive tract, the muscularis externa propels the material along the alimentary canal.... 

.

The small intestine is the site where most of the nutrients from ingested food are absorbed. It is covered in wrinkles called rugae, from which project microscopic finger-like pieces of tissue called villi Villus

Villi are tiny, finger-like structures that protrude from the wall of the intestine [i] and have additio ... 

. The purpose of these wrinkles and projections is to increase surface area for absorption of nutrients. Furthermore, each villus is covered in microvilli Microvillus

A microvillus is a small extension of the cell surface of absorptive and secretory epithelial cell [i]s, ... 

, which again increase the surface area manyfold. Each villus contains a lacteal and capillaries. The lacteal absorbs the digested fat Fat

Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely ins... 

 into the lymphatic system Lymphatic system

The lymphatic system is a complex network of lymphoid organs, lymph node [i]s, lymph ducts [i] ... 

 which will eventually drain into the circulatory system Circulatory system

A circulatory system is an organ system [i] that moves substances to and from cells [i]; i ... 

. The capillaries absorb all other digested nutrient Nutrient

A nutrient is any element or compound necessary for or contributing to an organism's metabolism [i], gro ... 

s. As well, the surface of the cells on the microvilli are covered wih a brush border of proteins which helps to catch a molecule-thin layer of water within itself. This layer, called the "unstirred water layer," has a number of functions in absorption of nutrients.

Although the small intestine is much longer than the large intestine , it is referred to as such due to its comparatively smaller diameter. On average, the diameter of the large intestine of an adult human measures approximately 3 times the diameter of the small intestine. Upon viewing accurate diagrams of the digestive system, non-medically trained personnel often initially express bemusement as to why the obviously longer portion of the digestive system is referred to as the small intestine.

Functions

The digestion of proteins into peptides and amino acids principally occurs in the stomach but some also occurs in the small intestine. The small intestine is where the most chemical digestion takes place; peptides are degraded into amino acid Amino acid

In chemistry [i], an amino acid is any molecule [i] that contains both amine [i] and carboxyl [i] functional group [i] ... 

s; lipid Lipid

Lipids are a class of hydrocarbon [i]-containing organic compound [i]s essential for the structure and f ... 

s are degraded into fatty acid Fatty acid

In chemistry [i], especially biochemistry [i], a fatty acid is a carboxylic acid [i] , often with a long ... 

s and glycerol Glycerol

Glycerol, also well known as glycerin and glycerine, and less commonly as propane-1,2,3-t... 

; and carbohydrate Carbohydrate

Carbohydrates are chemical compound [i]s that contain oxygen [i], hydrogen [i], and carbon [i] atom [i]s ... 

s are degraded into simple sugars .

Small Intestine Disorders

  • Small intestine cancer Small intestine cancer

    In oncology [i], small intestine cancer, also small bowel cancer and cancer of the small bowel' ... 

  • Small intestine obstruction
    • Obstruction from external pressure
    • Obstruction by masses in the lumen
  • Paralytic ileus
  • Maropthisis
  • Crohn's disease Crohn's disease

    Jane Seymour Fonda is an American [i] actress [i], writer [i], political activist [i] ... 

  • Celiac disease Coeliac disease

    [i] disorder of the [[small bowel]... 

  • Carcinoid Carcinoid

    Carcinoid, also carcinoid tumour and carcinoid tumor, is a slow-growing but often malignant [i]... 

  • Meckel's Diverticulum Meckel's diverticulum

    A Meckel's diverticulum, a true congenital [i] diverticulum [i], is a small bulge in the small intestine ... 

  • Gastric dumping syndrome
  • Infectious diseases
    • Giardiasis
    • Scariasis
    • Tropical sprue
    • Tapeworm infection
  • Mesenteric ischemia
  • Short bowel syndrome
  • Inguinal hernia

References

Solomon et. al Biology Sixth Edition, Brooks-Cole/Thomson Learning ISBN 0-03-033503-5

See also

  • Intestinal juice
  • Colon

External links