1、The Digestive System,Exocrine gland-with duct,Constituents of multicellular gland: secretory portion: tubular,acinar or tubuloacinar gland duct: passage of secretions,Exocrine gland-without duct,Exocrine gland,Salivary gland,Acinus: mucous acinus, serous acinus ,mixed acinus Duct: intercalated duct,

2、striated duct,interlobular duct and common duct,Salivary gland,Serous acini,Mucous acini,Mixed acini and semilune,Semilune: several serous cells arranged like half-moon in the mixed acinus,Salivary glands,1. components: parotid gland,submandibular gland and sublingual gland,etc. 2. function: secreti

3、ng saliva.,The characteristics of 3 pairs of salivary glands,Parotid gland-pure serous gland,Submandibular gland-mixed gland,Sublingual gland-mixed gland,Pancreas,Parenchyma: exocrine portion: pancreatic secretions involved in food-digestion. endocrine portion(pancreas islet): secreting hormones,1.

4、Exocrine portion,acini,ducts,Consists of serous cells surrounded by basal lamina， Without myoepithelial cells, With several centro-acinar cells in acinus cavity.,Long I.D. ,no S.D.,Exocrine portion of pancreas,Exocrine portion of pancreas,2. Endocrine portion (pancreas islet),Diabetes: absence or in

5、adequate amounts of insulin.,Liver,The largest digestive gland. The C.T.sends the septa into the parenchyma, separating the hepatic lobules. The portal area is present at the corner of the lobules.,Classic hepatic lobule,It is a structural unit of liver. Components Hepatic plates: a single layer of

6、hepatocytes arranged in radial. Sinusoids: between hepatic plates and anastomose with each other. Central vein: occupies the centre of the liver lobule.,hepatocyte,3 functional surfaces:sinusoidal., canalicular., intercellular. LM: Profile:large,polyhedral in shape. Cytoplasm:rich in Mitochondria, G

7、olgi complex, SER,RER, lipid droplets, glycogen,etc. Nucleus: large,central,lightly stained, with obvious nuceulus. EM: numerous microvilli protruding into sinusoids and bile canaliculi.,Function of hepatocyte,1.Bile secretion 2.Synthesis and storage 3.Detoxification and inactivation 4.Defence :rela

8、ted to Kuffer cell 5.Hemopoiesis,Bile canaliculus,It is a small canal formed by opposed grooves In the surface of adjacent hepatocytes.,Bile canaliculi,Sinusoid,Kuffer cell : macrophage in sinusoid,Space of Disse,Space between hepatocytes and endothelium. Microvilli of hepatocytes protrude into it,

9、which enhance the exchages of materials. Storing fat cells :in space of Disse.responsible for the storage of Vit.A and production of fibers.,Portal area（portal canals）portal triad:,Interlobular arteries,Interlobular veins,Interlobular bile ducts,Hepatic artery,Portal vein,Common bile duct,Hepatic ci

10、rculation,Common bile duct Portal vein Hepatic artery Hepatic vein,Interlobular bile ducts Interlobular vein Interlobular artery vein,Bile canaliculi sinusoids Central vein,Hepatic hilum,Hepatic lobule,Portal area,Key points,1. The structure and function of pancreas.(exocrine portion and endocrine portion),the cellular components of p