The gallbladder is a pear-shaped sac, about 7 to 10 cm long with an average capacity of 30 -50 mL containing bile

When obstructed, the gallbladder can distend markedly and contain up to 300 mL
The gallbladder is located in a fossa on the inferior surface of the liver that is in line with the anatomic division of the liver into right and left liver lobes
The gallbladder is divided into four anatomic areas
  • The fundus
  • The corpus (body
  • The infundibulum
  • The neck

The fundus is the rounded, blind end that normally extend 1 to 2 cm beyond the liver's margin. It contains most of the smooth muscles of the organ, in contrast to the body, which is the main storage area and contains most of the elastic tissue

The body extends from the fundus and tapers into the neck, a funnel-shaped area that connects with the cystic duct

The neck usually follows a gentle curve, the convexity of which may be enlarged to form the infundibulum or Hartman's pouch
The neck lies in the deepest part of the gallbladder fossa and extends into the free portion of the hepatoduodenal ligament
the same peritoneal lining that covers the liver covers the fundus and the inferior surface of the gallbladder

  The gallbladder has a complete peritoneal covering, and is suspended in a mesentery off the inferior surface of the liver, and rarely it is embedded deep inside the liver parenchyma (an intrahepatic gall­ bladder

The gallbladder is lined by a single, highly-folded, tall columnar epithelium that contains cholesterol and fat globules. the mucus secreted into the gallbladder originates in the tubuloalveolar glands found in the mucosa lining the infundibulum and neck of the gall­ bladder, but are absent from the body and fundus

The epithelial lin­ing of the gallbladder is supported by a lamina propria. The muscle layer has circular longitudinal and oblique fibers, but without well­ developed layers

The perimuscular subserosa contains connective tissue, nerves, vessels, lymphatics, and adipocytes. It is covered by the serosa except where the gallbladder is embedded in the liver

The gallbladder differs histologically from the rest of the gastrointestinal tract in that it lacks a muscularis mucosa and submucosa
Blood supply

 Arterial supply

The cystic artery that supplies the gallbladder is usually a branch of the right hepatic artery
The course of the cystic artery may vary, but it nearly always is found within the hepa­tocystic triangle, the area bound by the cystic duct, common hepatic duct, and the liver margin (triangle of Calot

When the cystic artery reaches the neck of the gallbladder, it divides into anterior and pos­terior divisions

 NB ; the cystic artery and cyst duct are very important structures and most be known their anatomy well because both structures are ligated and divided in removal of gall bladder by operation called cholecysrectomy

Venous drainage

Venous return is carried either through small veins that enter directly into the liver, or rarely to a large cystic vein that carries blood back to the portal vein

Lymphatic drainage

Gallbladder lymphatics drain into nodes at the neck of the gallbladder called calot,s node

Frequently, a visi­ble lymph node overlies the insertion of the cystic artery into the gallbladder wall

Nerve supply

The nerves of the gallbladder arise from the vagus and from sympathetic branches that pass through the celiac plexus

The preganglionic sympathetic level is thoracic T 8 and T9. Impulses from the liver, gallbladder, and the bile ducts pass by means of sympathetic afferent fibers through
the splanchnic nerves and mediate the pain of biliary colic

The hepatic branch of the vagus nerve sup­plies cholinergic fibers to the gallbladder, bile ducts, and the liver
The vagal branches also have peptide-containing nerves containing agents such as substance P. somatostatin, enkephalins, and vasoactive intestinal polypeptide

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