L3-Biliary passage & Exocrine pancreas Team 443.pdf

Biliary passage & Exocrine pancreas Color index: -Main text -important -female slides -male slides -Dr.note -Extra Editing File [ Gastrointestinal & Nutrition Block | Histology ] Objectives At the end of this lecture, you should be able to answer the following (objectives): identify & describe t...

Biliary passage & Exocrine pancreas Color index: -Main text -important -female slides -male slides -Dr.note -Extra Editing File [ Gastrointestinal & Nutrition Block | Histology ] Objectives At the end of this lecture, you should be able to answer the following (objectives): identify & describe the histological features of ● Intrahepatic biliary passages. ● Extrahepatic bile ducts. ● Gallbladder. ● Exocrine pancreas. Table of contents: Common hepatic duct Biliary passages Gallbladder Pancreas This lecture was presented by: Dr. Mohammed Atteya Prof. Raeesa Abdultawab Biliary passages Outside Liver Within Liver Extrahepatic passage Intrahepatic passage 1 Zoomed! Bile ductules ( canals of hering) 1 2 2 3 Intralobular duct 1. It’s formed of the union of the right & left hepatic. 2. It’s formed of the union of the cystic duct from gallbladder & common hepatic duct. Biliary passages: intrahepatic Structure / Features Epithelium Description (See previous slides’ Pictures to understand the description) ● They are the First portions of the bile duct system. None (No Epithelium) Bile canaliculi - Limited only by cell membranes of 2 hepatocytes. - Narrow channels between hepatocytes. Bile ductules (Canals of Hering) Composed of Cuboidal epithelial cells Might asked about called Cholangiocytes. the structure name Interlobular bile ducts - Are in portal areas - Lined by Simple cuboidal epithelium (Cholangiocytes) then become Simple columnar epithelium (Near the porta hepatis) ● Microvilli project from the hepatocyte into the bile canaliculi → increasing the surface area. ● Tight junctions between the cell membranes of the 2 hepatocytes prevent leakage of bile. First: Bile canaliculi empty into bile ductules (Near peripheral portal areas). Then: After a short distance, these ductules Collect and end in the interlobular bile ducts in the portal areas. First: Merge to form larger ducts (In the portal areas). Then: eventually unite to form the right & left hepatic ducts. Picture Common Hepatic duct Structures Mucosa Contents Description ●Epithelium: Simple columnar. ● Formed by union of right ●Lamina propria. & left hepatic ducts. ● Joins the cystic duct (arising from the gallbladder) forming the common bile duct. Muscularis Bundles of smooth muscle fibers (In all directions). Adventitia ● Loose areolar C.T. ● Similar in structure to the ● NOT covered by Mesothelium wall of (Gallbladder & other → Peritoneum. extrahepatic bile ducts). Gallbladder A Saclike structure that stores, concentrates and releases Bile The wall of gallbladder is formed of : Structures Mucosa (Highly folded) Muscularis Contents Epithelium : Simple columnar epithelium. Lamina propria: contains Mucous glands in the neck of gallbladder. Bundles of smooth muscle fibers (In all directions). (Fundus= serosa and other section Adventitia) - Gallbladder is dilated to store the bile because it’s not secreted immediately to the duodenum until there’s fat because the bile contain enzymes for Serosa or Adventitia emulsification (‫ )ﺗﻔﻛﯾك‬not digestion. - Gallstones developed when there is imbalance between concentrates and release of bile Thanks 439 Pancreas Parenchyma Pancreas is a mixed gland: stroma Capsule, Septa & Reticular fibers Exocrine part/glands Endocrine part/glands Produce digestive pancreatic enzymes Eg: Acini & Ducts Produce Hormones Eg: Islets of Langerhans A B Exocrine Pancreas Structure / Features Pancreatic Acini (serous acini) Description Secretion: Thin fluid rich in digestive pancreatic enzymes Centroacinar cells: ●Nuclei in the center of the acini ●Represent the beginning of the ducts No myoepithelial cells around the acini The pancreatic duct shoved into lumen of acini looks like the parotid gland but differ in the secreted enzymes and have centroacinar cells with not prominent intralobular ducts Pancreatic Acinar Cells Duct System ● Pyramidal in shape ● Nuclei are basal & rounded & vesicular ● Cytoplasm : Basal part Basophilic (due to abundant rER). Apical part Acidophilic (due to secretory granules) ● Centroacinar cells: Low cuboidal ● Intercalated ducts: Low cuboidal ● Intralobular ducts (Not prominent)*: Low columnar ● Interlobular ducts: Simple columnar ● Main pancreatic duct: simple columnar That's how you differentiate between the Pancreas and the Parotid gland * Picture Pancreas VS Parotid Gland pancreas Low Power Magnification Parotid Gland High Power Magnification Low Power Magnification Most Prominent Structure Islets of langerhans (Red Arrows): Pale spherical collection of cells inside acini (Red circle) Interlobular ducts (Green circle) High Power Magnification Most Prominent Structure Intralobular ducts (Green circle): Red colored striated/Secretory ducts SUMMARY Biliary passages Intrahepatic passage: ● Bile canaliculi: (No Epithelium), Limited by cell membranes of 2 hepatocytes ● Bile ductules: Cuboidal epithelial cells called Cholangiocytes ● Interlobular bile ducts: Simple cuboidal epithelium→Simple columnar epithelium Extrahepatic passage Common Hepatic duct Mucosa: ● Epithelium: Simple columnar ● Lamina propria Muscularis: Bundles of smooth muscle fibers Adventitia: ● Loose areolar C.T ● NOT covered by Mesothelium → Peritoneum Gallbladder Mucosa: ● Epithelium : Simple columnar epithelium. ● Lamina propria: contains Mucous glands in the neck of gallbladder Muscularis: Bundles of smooth muscle fibers Pancreas Stroma: Capsule, Septa & Reticular fibers Parenchyma: ● Exocrine part: Produce digestive pancreatic enzymes ● Endocrine part: Produce Hormones MCQs 01 Which of the following project from the hepatocyte into the bile Canaliculi? A- Flagella 02 B-Simple cuboidal C- Simple columnar epithelium epithelium Canals of Hering are composed of? B- simple columnar C-simple squamous A- cholangiocytes epithelium epithelium 03 B- Common hepatic duct C-Bile ductules D-Right & left hepatic ducts Which of the following is a feature of Pancreatic Acinar Cells? B- Cells are A- Cells are pyramidal in shape tubular in shape 05 D-stratified columnar epithelium Which of the following is intrahepatic passages? A- Common bile duct 04 D-Microvilli C-Nuclei are central D-The cytoplasm is completely basophilic The basal part of Pancreatic acinar cells is basophilic due to? A- Myoepithelial cells B- Abundant C-Secretory granules sER Answer key: 1. D 2. A 3. C 4. A 5. D D- Abundant rER This Lecture is done by: Members ● Hamad Alyahya ● Khalid AlRasheed ● Faisal Alzuhairy ● Abdullah Aldhuwaihy ● Fahad Almughaiseeb ● Abdulrahman Alosleb ● Abdulrahman Alomar ● Omar Banjar ● Yousof Badoghaish ● Waad Alanazi ● Raghad Almuslih ● Reema Alzughaibi ● Retal Alshohail ● Raghad Alothman ● Shaden Alhazzani Leaders ● Khalid Alanezi ● Waad alqahtani Reviewed by ● Academic leaders