Gallbladder & extrahepatic bile ducts
General
Anatomy, histology & embryology
Author: Hanni Gulwani, M.B.B.S.
Topic Completed: 1 September 2012
Minor changes: 17 April 2021
Copyright: 2003-2021, PathologyOutlines.com, Inc.
PubMed Search: Gallbladder histology[TIAB]
Table of Contents
Definition / general | Anatomy | Physiology | Diagrams / tables | Micro description - gallbladder | Micro description - extrahepatic bile ducts | Microscopic (histologic) images | Positive stains | Additional referencesCite this page: Gulwani H Anatomy, histology & embryology. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/gallbladderhistology.html. Accessed May 11th, 2021.
Definition / general
- Has mucosa, muscularis propria and serosa on free surface
- No muscularis mucosa or submucosa is present
Anatomy
- Pear shaped saccular structure for bile storage in gallbladder fossa of posterior right hepatic lobe
- Attached to liver by loose connective tissue and to duodenum by cholecystoduodenal ligament
- 10 x 4 cm but depends on volume of bile (normal 40 - 70 ml)
- Wall thickness 1 - 2 mm
- Has fundus, body and neck
- Distal fundus: extends beyond anterior liver margin
- Central body: most of gallbladder
- Neck: narrows as it joins the cystic duct
- Cystic duct: 3 cm tubular structure, located in right free edge of lesser omentum, has spiral valve of Heister
- Infundibulum: portion of body that joins the neck
- Hartmanns pouch: dilation in infundibulum, may be due to chronic inflammation
- Vasculature: supplied by cystic artery, usually a branch of right hepatic artery; variations of arteries may be dangerous during surgery
- Right and left hepatic ducts:
- 3 - 4 mm in diameter, within hepatoduodenal ligament, join to form common hepatic duct in porta hepatis (hilum of liver) within 1 cm of their exit from liver; variations may be dangerous during surgery
- 10 - 30% have variation of 2 right sided ducts that join separately with left hepatic duct, common hepatic duct or cystic duct
Common hepatic duct:- 2 - 8 mm, 1 - 5 cm long, joins cystic duct (1 - 3 cm long) to form common bile duct
Common bile duct:- 2 - 9 cm long, passes posterior to first portion of duodenum, traverses the head of pancreas, enters the second part of duodenum through the ampulla of Vater and discharges gallbladder contents into duodenal lumen
- 60% have common channel for pancreatic duct and common bile duct
- Remainder have 2 ducts in parallel
Cystic duct:- Attaches gallbladder to extrahepatic bile duct, marks division between common hepatic duct and common bile duct
- Usually 2 - 4 cm
- Contains spiral valves of Heister
Sacculi of Beale:- Tiny pits that are infoldings of surface epithelium and give mucosa a reticular macroscopic appearance
Spiral valves of Heister:- Folds in proximal mucosa of cystic duct, supported by underlying smooth muscle fibers
- Regulates degree of gallbladder distension
- Regional lymph nodes: lymph node present at gallbladder neck or cystic duct drains to hepatic hilar nodes (along common bile duct, hepatic artery, portal vein, cystic duct); also celiac, periduodenal, peripancreatic and superior mesenteric nodes
- Right and left hepatic ducts:
Physiology
- Bile excretion is normally 500 - 1000 ml/day
- Bile is concentrated 5 - 10x via active absorption of electrolytes accompanied by passive movement of water
- Cholecystokinin causes gallbladder contraction and release of stored bile into gut
- Bile is critical for intestinal absorption of dietary fat but the gallbladder is not
- Bile is 2/3 bile salts, bicarbonate rich, has 3% organic solutes
- 95% of secreted bile salts is reabsorbed in ileum and returned to liver via portal blood, called enterohepatic circulation of bile salts
- Cholesterol is eliminated by loss of 0.5 g of bile salts per day>
- Cholates, chenodeoxycholates, deoxycholates, lithocholates, ursodeoxycholates
- Major hepatic products of cholesterol metabolism
- Family of water soluble sterols with carboxylated side chains
- Are highly effective detergents, solubilize water insoluble lipids secreted by the liver (usually lecithin) into the biliary tree and promote dietary lipid absorption within the gut
Lecithin (phosphatidylcholine):
- Hydrophobic, nonaqueous
- Has minimal solubility in water
Diagrams / tables
Images hosted on other servers:
Relationship to liver
Extrahepatic bile ducts
Micro description - gallbladder
Mucosa:
Surface epithelium:
Lamina propria:
Muscular layer:
Adventitia:
Peritoneum:
Aberrant bile ducts (ducts of Luschka):
Rokitansky-Aschoff sinuses:
Larger accessory bile ducts:
Mucin secreting accessory glands:
- Variable branching folds, more prominent if gallbladder not distended
Surface epithelium:
- Composed of single layer of uniform, tall columnar cells with basal nuclei, indistinct nucleoli, pale cytoplasm due to sulfomucins
- Few PAS+ apical vacuoles; also pencil cells (small, darkly staining columnar cells), inconspicuous basal epithelial cells, T lymphocytes
- No goblet cells, myoepithelial cells or melanocytes
- Neck region has tubuloalveolar mucus glands that secrete sulfo, sialo and neutral mucin and contain neuroendocrine cells
- True glands are not present outside the neck
Lamina propria:
- Loose connective tissue with blood vessels, lymphatics, occasional chronic inflammatory cells (IgA secreting plasma cells), no neutrophils
Muscular layer:
- Circular, longitudinal and oblique smooth muscle fibers without distinct layers, resembles muscularis mucosa
- Adjacent to lamina propria without an intervening submucosa
Adventitia:
- Perimuscular connective tissue composed of collagen, elastic tissue, fat, vessels, lymphatics, nerves, paraganglia
Peritoneum:
- Lines gallbladder that is not directly attached to liver, is continuous with that of liver
Aberrant bile ducts (ducts of Luschka):
- Present in 10% of cholecystectomy specimens, often buried in gallbladder wall adjacent to liver, may contain collar of fibrous tissue, may communicate with intrahepatic bile ducts
- Histologically composed of lobular aggregates of small ductules lined by bland cuboidal to columnar biliary type epithelium (Am J Surg Pathol 2011;35:883)
Rokitansky-Aschoff sinuses:
- Outpouchings of gallbladder mucosa that penetrate into muscle wall
- May be acquired herniations
Larger accessory bile ducts:
- Join with cystic or hepatic ducts, may be present within gallbladder bed
Mucin secreting accessory glands:
- Prominent near terminus of common bile duct
Micro description - extrahepatic bile ducts
Surface epithelium:
Peribiliary mucous glands:
Subepithelial region:
Muscle layer:
- Composed of tall, uniform, columnar cells
- Mucosa forms irregular pleats or small longitudinal folds
Peribiliary mucous glands:
- Considered a local progenitor cell niche in extrahepatic biliary epithelium (Liver Int 2012;32:554)
- Unevenly distributed within large intrahepatic ducts and all extrahepatic bile ducts
- Lobular architecture; are surrounded by fibroconnective tissue (important in differentiating from well differentiated carcinoma)
Subepithelial region:
- Dense, hypocellular connective tissue, few lymphocytes
- Overlies loose connective tissue with elastic fibers and smooth muscle fibers that are most prominent distally but absent or sparse proximally
Muscle layer:
- Not well defined until distal common bile duct / lower 1/3 of extrahepatic bile duct (Am J Surg Pathol 2000;24:660)
- Upper 1/3 has no muscle layer or scattered muscle fibers
Microscopic (histologic) images
Images hosted on other servers:
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Cross section of gallbladder
Extrahepatic bile duct and gallbladder
Positive stains
- Surface epithelium: EMA, low molecular weight keratin, alpha-1-antitrypsin, alpha-1-antichymotrypsin, polyclonal CEA
- Peribiliary glands: amylase, trypsin, lipase
Additional references
