Small Intestine Secretion
- Secretions of the small intestine occur from two types of histological structures: Brunners Glands and Crypts of Lieberkuhn. Brunners Glands mostly secrete mucus which is designed to protect the small intestine mucosa from damage by stomach acid. Secretion from Lieberkuhn's Crypts takes place from two different cellular subtypes. Cryptic goblet cells secrete mucus which helps lubricate food and protects the intestinal mucosa whereas cryptic enterocytes secrete large volumes of fluid (nearly 2L/day) that is added to the intestinal chyme and aids in digestion and absorption. The fluid secreted by cryptic enterocytes is roughly of the same electrolyte composition as extracellular fluid. Small intestinal secretions are largely regulated through local reflexes which sense irritation due to the presence of chyme within the intestine.