消化腺（全英文）课件.pptVIP

* Digestive System Digestive Glands Components digestive glands found in the wall of digestive tract accessory digestive glands: salivary glands / pancreas / liver General structure * Parenchyma (functional portion of an organ, as distinguished from the supporting tissue): acini / gland cells duct * Stroma (unfunctional portion of an organ): capsule, CT inside. Salivary glands * Parotid * Submandibular G. * Sublingual G. Three types of acini * serous * mucous * seromucous Function: * moistening food * carbohydrate digestion * Secrete IgA Pancreas positioned retroperitoneally on the posterior wall of the abdominal cavity at the level of the second and third lumbar vertebrae. no distinct capsule, but is covered by a thin layer of LCT both an exocrine endocrine gland. * exocrine part: produces pancreatic juice * endocrine part: produce hormones Components of the exocrine pancreas consists of serous glands acini filled with acidophilic zymogen granules intercalated duct extends into the centre of the acini, which is lined by centroacinar cells duct system: intercalated ducts (low columnar or cuboidal epith.) Interlobular ducts (columnar epith.) Main pancreatic ducts ( tall columanr epth.) major duodenal papilla Function of pancreatic juice: * Trypsin, chymotrypsin carboxypeptidase hydrolyse proteins; * ribonuclease deoxyribonuclease split nucleic acids; * amylase hydrolyses starch glycogen * lipase hydrolyses triglycerides into fatty acids and monoglycerides * cholesterol esterase breaks down cholesterol esters into cholesterol and a fatty acid. Components of the Endocrine * Islands of Langerhans scattered throughout the exocrine pancreas. * Vascularization (many fenestrated cap.) is more extensive than that of the exocrine acini. * Three different t