Small intestine

In biology the small intestine is the part of the gastrointestinal tract between the stomach and the large intestine (colon). In humans over 5 years old it is about 7m long. It is divided into three structural parts: duodenum, jejunum and ileum. Food from the stomach is allowed in to 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.

Related Topics:
Biology - Intestine - Gastrointestinal tract - Stomach - Large intestine - Human - Duodenum - Jejunum - Ileum - Pylorus - Pyloric sphincter - Peristalsis

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The small intestine is the site where most of the nutrients from ingested food are absorbed. There are microscopic finger-like projections called villi covering the small intestinal walls which increase surface area for absorption. Each villus contains a lacteal and capillaries. The lacteal absorbs the digested fat into the lymphatic system which will eventually drain into the circulatory system. The capillaries absorb all other digested nutrients.

Related Topics:
Villi - Lacteal - Fat - Lymphatic system - Circulatory system - Nutrient

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