Lecture 2 ESS_3rd semester MICROSCOPIC STRUCTURE OF LIVER, GALLBLADDER, GALL DUCTS, AND PANCREAS OVERVIEW OF DEVELOPMENT OF THE ALIMENTARY CANAL hepar1 MICROSCOPIC STRUCTURE OF LIVER - is the largest gland of the body - is of endodermal origin - it consists of the connective tissue, parenchyma, and blood vessels connective tissue – 2 sites: - fibroconnective capsule (capsule of Glisson) – on the surface of liver - interstitial connective tissue within parechyma - is poor in amount distinct is in portal areas (portal canals) – sites where usually meet 3 hepatic lobules (structural units of the parenchyma) portal areas have triangular shape (triangles of Glisson) portal area contains triad of Glisson: - interlobular vein (from v. portae) - interlobular artery (from hepatic artery) - bile duct jatra_lalucky1 kopie Parenchyma hepatic lobules (lobules of a central vein) and intrahepatic bile ducts lobules are polyhedral prisms of 1 to 2 mm high nad wide in cross sections lobules usually show hexagonal profile with a central vein in their centres F16_10 hepar2 hepatic lobule consists of hepatic cell plates (cords of Remak) alternating with sinusoids hepatic cell plates are made up of 1 or 2 rows of hepatocytes among them run bile canaliculi F16_10 hepar3 Trávící systém III - 2 Játra (hepar) Trávící systém III - 1 Játra - schéma jatra_lalucky1 kopie F16_12 Trávící systém III - 13 Játra - krysa Bez názvu7 kopie hepatocytes are mostly polygonal and often binucleate cells the cytoplasm is eosinophilic and slightly granular. The plasma membranes of two adjacent hepatocytes are smooth except the surfaces limited the bile canaliculi and perisinusoidal spaces. hepatic sinusoids = thin vascular channels d. cca 20 mm, length of 500 mm or more, branched empty into a central vein lined with endothelium + phagocytic Kupffer cells Trávící systém III - 3 Centrum jaterního lalůčku F16_11 * F16_12 Trávící systém III - 12 Kupfferovy b Kupffer cells F16_11 hepar3 bile canaliculi diameter cca 1-2 mm surrounded with plasmalemmas of adjacent hepatocytes begin blindly near the central vein and run to the periphery of the lobule open into the canals of Hering Intrahepatic bile ducts: canals of Herring interlobular bile ducts F16_10 portal area.jpg Blood circulation of the liver 2 circulations - nutritive one (hepatic artery) - oxygenated bood - functional one (portal vein) - venous blood rich in absorbed products division of blood streams - 20 to 30 % of blood flows nutritive through circulation - 80-70 % of blood flows through functional circul. blood of both circulations meets at the level of hepatic sinusoids hepatic artery interlobular artery interlobular arterioles proper (portal areas) (surface of hepatic lobules interlobular interlobular venules HEPATIC SINUSOIDS veins(portal areas) (surface of hepatic lobules vena portae hepatic veins sublobular veins central veins inferior vena cava Functional circulation Nutritive circulation F16_11 F16_10 Hepatic lobus (lobule of a central vein) Concept of a portal lobule portal lobule - has triangular shape its centre is formed by a portal area and tissue draining bile into bile duct of that portal area liver_lobules.jpg hepar6 Zones of hepatic acinus: 1.zone of permanent activity 2.transient zone 3.quiescent zone Extrahepatic biliary passages right + left hepatic duct common hepatic duct cystic duct common bile duct (d. choledochus) gallbladder - 3 layers - mucosa - muscular l. - serous coat (partly also adventitia) Wall: 1.simple columnar epithelium 2.lamina basalis 3.dense collagen conn. tissue Bez názvu8 kopie Bez názvu 9 kopie wall of the gallblader MICROSCOPIC STRUCTURE OF PANCREAS - gland of 120 -130 g - it lies in the concavity of the duodenum (head, body and tail) - pancreas consists of a) connective tissue - capsule + septae b) parenchyma – exocrine + endocrine glandular tissue lobules - serous acini + ducts - islets of endocrine cells (islets of Langerhans) pancreas2 F16_06 Exocrine pancreas : serous acini + ducts Trávící systém III - 17 Pankreas Trávící systém III - 18 Pankreas - Langerhansův ostrůvek Endocrine pancreas: islets of Langerhans A cells, B cells, D cells, PP cells - pancreatic polypeptide Bez názvu 10 kopie GEPcells • • Stomodeum • Oropharyngeal membrane • • Primitive gut • foregut • midgut • hindgut • • Cloacal membrane • Proctodeum • • • •ventral mesenterium •dorsal mesenterium embryo_sagittal OVERVIEW OF DEVELOPMENT OF THE ALIMENTARY CANAL Trávící systém III - 22 Frontal view of the alimentary canal (5th week) branchialapp Trávící systém I - 37 Branchial apparatus of the embryo and its fate arches1_develop arches2_develop Zabernibrazdy_deriv_schemaupr kopie pouches_develop Zabernibrazdy_deriv_schemaupr kopie tongue_develop thyroid_develop Development of pharynx, esophagus and stomach Pharynx - constitutes after completion of the branchial apparatus development, when process of separation of branchiogenic organs was finished Esophagus - ventrally proliferates respiratory diverticulum, initially very short, by 7 th week - final length Stomach - appears as fusigorm dilatation of the caudal part of the foregut is suspended by ventral and dorsal mesogastrium Trávící systém II - 34 Trávící systém III - 25 Stomach 5th week - dorsal wall grows rapidly than vetral - major and lesser curvatures 6th week - undergoes rotation movement according to axis: A/longitudinal major c. to the left (right side becomes the dorsal side lesser c. to the right (lect side becomes the ventral side B/ sagittal cardiac part moves inferiorly pyloris part moves rather superiorly Trávící systém II - 36 Trávící systém II - 37 Trávící systém II - 34 midgut1_develop Development of the intestine midgut + hindgut midgut elongates to form 2 loops: - duodenal loop - C - shaped - midgut loop - U - shaped cranial limb caudal limb (jejunoileal) (ileocaecal) by primitive flexure of the coli hindgut - precloacal portion - cloaca Duodenum develops from duodenal loop, that rotates around the longitudinal axis to the right, rotation is connected with dislocation of mesenteries between the 5th and 6th w. comes to obliteration of the duodenal lumen, recanalization in the 8th w. midgut_develop rotationmidgut rotacepupkličky.jpg Development of the midgut loop rotacepupkličky1.jpg Trávící systém II - 39 Trávící systém II - 43 Trávící systém II - 45 Trávící systém II - 44 hindgut_develop EB_img10-kloaka_angl.jpg Trávící systém II - 47 Development of the hindgut liver_develop Development of the liver and biliary apparatus pancreas_develop Development of the pancreas vývjaterapa_Mitchell.jpg rotacepupkl.jpg