The absorption of nutrient occurs partly by diffusion v the wall of the tiny intestine.

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Key Points

digested food is able to pass into the blood ship in the wall of the small intestine through the process of diffusion. The inside wall, or mucosa, that the little intestine is covered in wrinkles or folds called plicae circulares that job microscopic finger-like pieces of tissue referred to as villi, which in turn have actually finger-like projections known as microvilli. The duty of the plicae circulares, the villi, and the microvilli is to rise the amount of surface area obtainable for the absorb of nutrients. Every villus transports nutrients to a network of capillaries and also fine lymphatic vessels called lacteals close to its surface.

Key Terms

villi: Tiny, finger-like projections the protrude native the epithelial lining the the intestinal wall. plicae circulares: these circular crease (known together the valves that Kerckring or the valvulae conniventes) are large, valvular flaps that project into the lumen the the bowel. diffusion: The action of diffusing or dispersing something, or the building of gift diffused or dispersed; dispersion.


Examples that nutrients absorbed by the small intestine encompass carbohydrates, lipids, proteins, iron, vitamins, and water.

The tiny Intestine

The small intestine is the component of the cradle tract between the stomach and also the big intestine where much of the digestion of food take away place. The primary duty of the little intestine is the absorb of nutrients and minerals found in food.


Intestinal villus: an image of a simplified structure of the villus. The thin surface layer appear above the capillaries the are associated to a blood vessel. The lacteal is surrounding by the capillaries.

Digested nutrients pass right into the blood vessels in the wall surface of the intestine through a procedure of diffusion. The inner wall, or mucosa, the the small intestine is inside wall with an easy columnar epithelial tissue.

Structurally, the mucosa is extended in wrinkles or folds dubbed plicae circulares—these space permanent attributes in the wall surface of the organ. They are distinctive from the rugae, which space non-permanent features that permit for distention and contraction.

From the plicae circulares project microscopic finger-like piece of tissue referred to as villi (Latin for shaggy hair). The separation, personal, instance epithelial cells additionally have finger-like projections known as microvilli. The duty of the plicae circulares, the villi, and also the microvilli is to rise the lot of surface area easily accessible for the absorption of nutrients.

Each villus has actually a network the capillaries and also fine lymphatic vessels dubbed lacteals close to its surface. The epithelial cells of the villi carry nutrients indigenous the lumen that the intestine right into these capillaries ( amino acids and carbohydrates) and also lacteals (lipids).

The took in substances space transported via the blood vessels to various organs that the body wherein they are supplied to build complicated substances, such together the proteins forced by our body. The food that remains undigested and unabsorbed passes right into the huge intestine.

Absorption of the bulk of nutrients takes place in the jejunum, with the following notable exceptions:

steel is took in in the duodenum. Vitamin B12 and also bile salt are took in in the terminal ileum. Water and lipids are soaked up by passive diffusion transparent the small intestine. Salt bicarbonate is absorbed by energetic transport and glucose and also amino mountain co-transport. Fructose is soaked up by promoted diffusion.

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Section of duodenum: section of duodenum v villi at the peak layer.

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