Absorption of Nutrients in the Intestine

Absorption of Nutrients

• Food molecules released by digestive processes are absorbed through epithelial cells of the intestinal mucosa.

Carbohydrate Absorption

• Disaccharides are broken down to monosaccharides by lactase, sucrase, and maltase enzymes embedded in epithelial cell membranes.
• Monosaccharides are rapidly absorbed through active transport and facilitated diffusion.

Protein Absorption

• Amino acids and dipeptides are absorbed through active transport.

Absorption into Bloodstream

• Absorbed molecules enter the bloodstream through capillaries of the villi.

Fat Absorption

• Small fatty acids enter blood vessels of the intestine directly.
• Large fatty acids, glycerol, and cholesterol enter mucosal cells by passive diffusion.
• Within mucosal cells, fatty acids and glycerol are resynthesized into fats and packaged into chylomicrons.
• Cholesterol is packaged into low-density lipoprotein (LDL) complexes.