Describe the structure of villi. How are lactaels different from villi in function? (2 marks )

The intestinal villi are small finger like projections that extend into the lumen of the small intestine. Each villus has many microvilli projecting from its epithelial surface, collectively forming a brush border. Villi are specialised for absorbtion and have very thin walls which are single cell thick. They have a rich blood supply to keep a concentration gradient. Villus capillaries collect amino acids and simple sugars.

Lacteals are lymphatic capillaries found in the villi of the small intestine. They absorb and transport large molecules, fats, and lipids in the digestive system mainly in the form of lipoproteins. The combination of fat and lymph in the lacteals is milky in appearance and is called chyle. This chyle is carried by the lacteals to the lymph vessels in the intestinal wall. Individual lacteals merge to form larger lymphatic vessels that transport the fats to the thoracic duct which empties into the left subclavian vein.