BILIARY PASSAGES & PANCREAS

OBJECTIVES:

1.Intrahepatic biliary passages. 2.Extrahepatic bile ducts. 3.Gall bladder. 4.Exocrine pancreas. Mind Map NOTE: Remember:the bile is synthesized in the liver Biliary Passages (hepatocytes) however the actual secretion happens in the bile as it functions as a storage sac.So we need to transport (by a duct) the bile to the gall bladder and another duct to transport it to the duodenum once it is needed. ❖ intrahepatic passages:

Bile Ductules (Canals of Hering) Interlobular Bile Bile canaliculi Ducts

- Narrow channels located between -Are in the portal areas. hepatocytes, limited only by the cell -Near the peripheral portal areas, bile membranes of 2 hepatocytes. canaliculi empty into bile ductules -Lined by simple cuboidal composed of cuboidal epithelial cells epithelium (becomes simple -They are the first portions of the bile called cholangiocytes. columnar epithelium near the porta duct system. hepatis).

-Microvilli project from the hepatocyte -After a short distance, these -Interlobular bile ducts merge to into the bile canaliculi, thus increasing ductules collect and end in the form larger ducts, which eventually the surface area. interlobular bile ducts in the portal unite to form the right and left areas.(see the picture in the coming -Tight junctions between the cell hepatic ducts.(see the picture in slide) membranes of the 2 hepatocytes the coming slide) prevent leakage of bile. Portal: Any of the spaces between the lobes of the liver Inter = between lobules of liver Tight junction: To prevent leakage Intra = inside the liver The color of the bile is green Porta hepatis: is a deep fissure in the inferior surface (Intrahepatic passage bile canaculi ) of the liver through which all the neurovascular structures (except hepatic veins) and hepatic ducts Any secretory cell has to have microvili > for more secretion or absorption enter or leave the liver Cont.Biliary Passages

❖ intrahepatic passages:

Bile Ductules Interlobular Bile Bile canaliculi (Canals of Hering) Ducts

Note: there is no epithelium, the lumen is formed between the two hepatocytes.

Microvilli tight junction

hepatocyte hepatocyte Cont.Biliary Passages ❖ Extrahepatic passages: Common Hepatic Duct Origin ● Formed by union of the right & left hepatic ducts.

Relations ● It joins the cystic duct, arising from the gallbladder, forming the common bile duct.

Structure (3 ● Similar in structure to the wall of gall bladder layers) : and other extrahepatic bile ducts.

Mucosa Muscularis Adventitia (only)

● Epithelium: ● bundles of C.T Simple smooth columnar. muscle fibers ● Lamina in all propria. directions. Gall Bladder

A saclike structure that stores, concentrates and releases bile. Its wall is formed of

Highly folded. bundles of smooth –Simple columnar muscle fibers oriented in epithelium. all directions. –Lamina propria: contains mucous glands in the neck of gall bladder.

Lumen contains the bile Fundus in gall bladder contains (peritonium (contains SEROSA (IN BODY (ADVENTATIA Without goblet cells and not ciliated ( except neck, the mucus is coming (from NECK of gallbladder Highly folded: because its function is storage Centroacinar cells: like grape root Pancreatic duct secrete into duodenum Pancreas No myoepithelium: because it’s a hormonal control

Stroma Capsule, septa and reticular fibers.

Produce digestive Exocrine Part: pancreatic Parenchyma Acini’s & ducts Pancreas is a mixed enzyme gland “endocrine & exocrine at the same time”. Endocrine part: Produces iselts of langerhan’s hormones Exocrine Pancreas

-They are serous acini: secreting a thin fluid rich in digestive -Centroacinar cells. pancreatic enzymes. -Intercalated ducts (low cuboidal). -Centroacinar cells: Their nuclei -Intralobular ducts ﻋﻛس) .(appear in the center of the acini. (NOT prominent parotid which wasال They represent the beginning of prominent ) the ducts. -Interlobular ducts. -No myoepithelial cells around the -Main pancreatic duct. acini.

Pyramidal in shape

Nuclei are basal

1- Basal Part Basophilic, due abundant rough ER Cytoplasm 2- Apical part Acidophilic, due to secretory granules Difference Between Parotid gland Pancreas

Parotid gland Pancreas

Interlobular duct Intralobular (prominent) ducts (NOT prominent)

There is No islets islets of of Langerhans Langerhans Summary

Biliary Intrahepatic Passages: Extrehepatic Passages: Passages:

1-Bile Canaliculi 2-Bile Ductules 3-Interlobular 4-RT & LT 5-common hepatic 6-Common (Canals of Hering) Bile Ducts Hepatic ducts duct: bile duct

Located: Narrow channels Near the peripheral Portal area located beween portal areas. hepatocytes composed -Microvilli (increase -composed of cuboidal -Lined by simple -Mucosa: of: epithelial cells called surface area) cuboidal –Epithelium: Simple cholangiocytes. epithelium -Tight junctions between (becomes simple columnar. the cell membranes of columnar –Lamina propria. epithelium near the 2 hepatocytes the porta hepatis). -Muscularis. prevent leakage of bile. -Adventitia. Summary

Exocrine Pancreas:

Pancreatic Acini:( serous acini) Pancreatic Acinar Duct System: Cells:

Centroacinar cells Pyramidal in shape.

Nuclei are basal..

-No myoepithelial cells around the acini. Cytoplasm: –Basal part basophilic.

–Apical part acidophilic.

GALL BLADDER PANCREAS

A saclike structure that stores, concentrates and releases bile. -Stroma: capsule, septa & reticular fibers. -Parenchyma: Pancreas is a mixed gland

-Mucosa: highly folded. •Exocrine part (acini & ducts): composed •Simple columnar. of: produces digestive pancreatic enzymes. •Lamina propria: mucous glands in the neck. -Muscularis. •Endocrine part (islets of Langerhans): produces -Serosa or adventitia. hormones. MCQs & SAQs

1) All of the following are from the intrahepatic passages EXCEPT? 4)Narrow channels located between hepatocytes & are limited only by the cellmembranes of 2 A-Interlobular bile ducts. hepatocytes? B-Bile canaliculi. Bile Canaliculi. C-Common hepatic duct. D-Canals of Hering. 5)What project from the hepatocyte into the bile canaliculi to increasing the surface area? 2)After a short distance, the cholsngiocytes collect and end in the? Microvilli.

A-Common bile duct. 6)Near the peripheral portal areas, bile canaliculi B-Interlobular bile ducts. empty into bile ductules composed of cuboidal C-Right & left Hepatic ducts. epithelial cells and these are called? D-Common hepatic duct. Cholangiocytes. 3)A saclike structure that stores, concentrates and releases bile is called?

A-Cystic duct. 1-C B-Hepatic ducts. 2-B C-Common bile duct.

D-Gallbladder. 3-D Motivation Corner

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