Question

Name three histological features that exist to increase the absorptive function of digestive tissues.

Answer 1

The wall of the small intestine is composed of the four layers present in the alimentary system.. The structures , which increase the absorptive surface area of the small intestine include circular folds, villi, and microvilli .These structures are mostly present in the proximal two-thirds of the small intestine, where the majority of absorption occurs.

circular fold also known as plica circulae is a deep ridge in the mucosa and submucosa. present from the  proximal part of the duodenum and ending near the middle of the ileum, these folds facilitate absorption. Their shape causes the chyme to spiral, rather than move in a straight line, through the small intestine. Spiraling slows the movement of chyme and provides the time needed for nutrients to be fully absorbed.

within the circular folds are small hairlike vascularized projections called villi that give the mucosa a furry texture. . these increases the surface area of the epithelium tremendously . The mucosal epithelium, primarily composed of absorptive cells, covers the villi. each villus contains a capillary bed composed of one arteriole and one venule, as well as a lymphatic capillary called a lacteal. The breakdown products of carbohydrates and proteins enter the bloodstream directly, but lipid breakdown products are absorbed by the lacteals and transported to the bloodstream via the lymphatic system.