Fundamentals in Gastroenterology
Gastroenterology is the field of medicine devoted specifically to treatment of the digestive system. The gastrointestinal tract is a tube-like structure which extends from the mouth to the anus. Histologically the gut comprises of four main layers: the mucosa, which comprises epithelial cells (enterocytes, endocrine cells and others), the lamina propria and the muscularis mucosae; the submucosal; two muscle layers, an inner thick circular layer and an outer thin longitudinal layer; and a serosal layer. Functionally, the gastrointestinal tract supplies the body, including the gut itself, with nutrients, electrolytes and water by performing five different functions: motility, secretion, digestion, absorption and storage. The gut coordinates these functions by two control systems, intrinsic and extrinsic.