Intestinal absorption

Intestinal absorption is the movement of digested nutrients, water, and ions from the intestinal lumen into the body through the intestinal lining.

Enterocyte: An absorptive epithelial cell lining the small intestine. Enterocytes take up nutrients and move them across the intestinal epithelium.
Small intestine: The digestive-tract region between the stomach and large intestine, consisting of the duodenum, jejunum, and ileum. Most nutrient absorption occurs across its extensive lining.
Malabsorption: Impaired uptake of nutrients from the digestive tract into the body. It is the clinical counterpart of inadequate intestinal absorption.
Digestion: The mechanical and chemical breakdown of food into smaller molecules. Digestion produces absorbable molecules; absorption then transfers them out of the lumen.
Brush border: The dense array of microvilli on the apical surface of intestinal epithelial cells. Its enzymes finish digestion, and its expanded surface supports nutrient uptake.
Intestinal villus: A fingerlike projection of the small-intestinal mucosa containing blood vessels and a lymphatic vessel. Villi expand the absorptive surface and connect it to circulation.
Celiac disease: An immune-mediated disorder in which gluten exposure damages the small-intestinal mucosa. Villus injury can reduce the surface available for nutrient uptake.
Secretion: The release of substances from cells or glands into a body compartment or onto a surface. Intestinal secretion moves fluid and solutes into the lumen, opposite the net direction of absorption.
Sodium-glucose cotransporter 1: A membrane protein that transports glucose or galactose into intestinal cells together with sodium ions. It uses the sodium gradient to absorb dietary glucose and galactose.
Microvillus: A microscopic projection of a cell's plasma membrane that increases its surface area. Enterocyte microvilli create the brush border where many absorption steps occur.

Linked from 16 pages