BILIARY PASSAGESBILIARY PASSAGES

Objectives:Objectives:

1.1.The student should be able to identify & The student should be able to identify & describe the histological features of describe the histological features of intrahepatic biliary passagesintrahepatic biliary passages..

2.2.The student should be able to identify & The student should be able to identify & describe the histological features of describe the histological features of extrahepatic bile ductsextrahepatic bile ducts..

3.3.The student should be able to identify & The student should be able to identify & describe the histological structure of describe the histological structure of gall bladdergall bladder..

Biliary PassagesBiliary Passages

Intrahepatic passages:Intrahepatic passages:

1-1- Bile canaliculi.Bile canaliculi.

2-2- Bile ductules (canals of Bile ductules (canals of Hering).Hering).

3-3- Interlobular bile ducts.Interlobular bile ducts.

Extrahepatic passages:Extrahepatic passages:

4-4- Right & left Hepatic Right & left Hepatic ducts.ducts.

5-5- Common hepatic duct.Common hepatic duct.

6-6- Common bile duct.Common bile duct.

Bile CanaliculiBile Canaliculi Narrow channels located Narrow channels located

between hepatocytes, limited between hepatocytes, limited only by the only by the cell membranes of 2 cell membranes of 2 hepatocyteshepatocytes..

They are the They are the first portions first portions of the of the bile duct system.bile duct system.

MicrovilliMicrovilli project from the project from the hepatocyte into the bile hepatocyte into the bile canaliculi, thus increasing the canaliculi, thus increasing the surface area.surface area.

Tight junctions Tight junctions between the cell between the cell membranes of the 2 hepatocytes membranes of the 2 hepatocytes prevent leakage of bile. prevent leakage of bile.

Bile Ductules (Canals of Hering)Bile Ductules (Canals of Hering)

Near the peripheral Near the peripheral portal areas, bile portal areas, bile canaliculi empty into canaliculi empty into bile bile ductulesductules composed of composed of cuboidal epithelial cells cuboidal epithelial cells called called cholangiocytescholangiocytes..

After a short distance, After a short distance, these ductules collect these ductules collect and end in the and end in the interlobularinterlobular bile ductsbile ducts in the portal areas. in the portal areas.

Interlobular Bile DuctsInterlobular Bile Ducts

Are in the portal areas.Are in the portal areas. Lined by Lined by simple cuboidal simple cuboidal

epithelium epithelium (becomes (becomes simple columnar simple columnar epithelium near the porta epithelium near the porta hepatis).hepatis).

Interlobular bile ducts Interlobular bile ducts merge to form larger merge to form larger ducts, which eventually ducts, which eventually unite to form the right and unite to form the right and left hepatic ducts.left hepatic ducts.

Common Hepatic DuctCommon Hepatic Duct Formed by union of the right Formed by union of the right

& left hepatic ducts. It joins & left hepatic ducts. It joins the cystic duct, arising from the cystic duct, arising from the gallbladder, forming the the gallbladder, forming the common bile duct.common bile duct.

Similar in structure to the wall Similar in structure to the wall of gall bladder and other of gall bladder and other extrahepatic bile ducts.extrahepatic bile ducts.

Mucosa:Mucosa:– Epithelium: Simple columnar.Epithelium: Simple columnar.– Lamina propria.Lamina propria.

Muscularis:Muscularis: bundles of smooth bundles of smooth muscle fibers in all directions.muscle fibers in all directions.

AdventitiaAdventitia..

GALL BLADDERGALL BLADDER

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

– Simple columnar epithelium.Simple columnar epithelium.– Lamina propria: contains Lamina propria: contains

mucous glands in the neck of mucous glands in the neck of gall bladder.gall bladder.

Muscularis:Muscularis: bundles of bundles of smooth muscle fibers oriented smooth muscle fibers oriented in all directions.in all directions.SerosaSerosa or or adventitiaadventitia..

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