BIO 11 Lecture Notes - Lecture 29: Gastric Pits, Ileocecal Valve, Gastric Acid
Document Summary
Muscularis externa of the stomach has an additional inner layer of smooth muscle with its fibers oriented obliquely. This layer allows the stomach to perform churning, a motion that pummels the food into a liquid called chyme. The mucosa is indented to form deep structures - gastric pits. Between the gastric pits, there are columnar cells and goblet cells, both secreting mucus that line and protect cells of the stomach from its own secretions. At the base of the gastric pits are multiple branched glands - gastric glands. They contain both endocrine cells that secrete hormones into the bloodstream and exocrine cells that secrete an acidic, enzyme-containing fluid called gastric juice into the lumen of the stomach. It starts in umbilical region and connected to pyloric part of stomach. Functions: mechanical and chemical digestion, absorption (nutrients), propulsion and secretion. Receives digestive fluids from stomach and the accessory glands (liver, gallbladder and pancreas) Firmly attached to the posterior abdominal wall.
