Gallbladder and bile

Summary

The gallbladder is an intraperitoneal organ derived from the endoderm that is located inferior to the liver. It is divided into a fundus, a body, and a neck. The gallbladder is perfused by the cystic artery, a branch of the right hepatic artery that drains into the cystic vein and the hepatic sinusoids. The main function of the gallbladder is bile storage. Bile is secreted by the liver and facilitates digestion, neutralization of gastric acid, fat absorption, and excretion of bilirubin and cholesterol. The biliary tract, which is divided into intrahepatic and extrahepatic bile ducts, transports bile to the intestine. The ductules are intrahepatic bile ducts that unite to form the left and right hepatic ducts, which drain bile from the liver. The extrahepatic bile ducts include the cystic duct and the common hepatic duct, which unite to form the common bile duct. The common bile duct unites with the pancreatic duct and drains into the hepatopancreatic ampulla in the duodenum. Excessive saturation of bile with cholesterol or bilirubin leads to gallstone formation. Diseases of the biliary tract include cholecystitis, primary sclerosing cholangitis, and biliary atresias among many others.

Gallbladder

The gallbladder is a hollow, pear-like-shaped (piriform) organ that lies on the cystic plate (gallbladder bed) under the liver segments IVB and V. The cystic plate is a fibroareolar tissue that attaches the superior surface of the gallbladder to the liver.

Anatomy

Function

  • Storage of bile
    • Bile drains from the liver via small bile ducts.
    • Cholecystokinin (CCK) stimulates the gallbladder to contract, which then releases bile through the cystic duct, into the second part of the duodenum.
  • Concentration of bile: by absorption of electrolytes and water

Vasculature

Innervation

Cholecystitis causes referred pain to the right shoulder region because the phrenic nerve originates from spinal nerves C3–C5, which also provide somatic sensation to the shoulder area.

References:[1]

Biliary tract

Anatomy

The portal triad consists of the hepatic artery, portal vein, and common bile duct.

Bile

Composition

Bile is a secretion produced by the liver and stored in the gallbladder that aids in digestion, neutralization of gastric acid, fat absorption, and excretion of bilirubin and cholesterol.

A deficiency of bile acids can result in fat malabsorption and cholesterol stones in the gallbladder.

Function

Enterohepatic circulation

Substances metabolized in the liver are excreted into the bile.

Gallstones

There are different types of gallstones (for more information on gallstone pathologies, see cholelithiasis and cholecystitis):

References:[2][3]

Embryology

Microscopic anatomy

Layers of the gallbladder wall:

References:[2]

Clinical significance

Disorders of the biliary tract

Disorders of the bile

  • 1. Kapoor VK. Gallbladder Anatomy. In: Gest TR. Gallbladder Anatomy. New York, NY: WebMD. https://emedicine.medscape.com/article/1900182-overview. Updated December 8, 2017. Accessed June 7, 2018.
  • 2. Standring S. Gray's Anatomy: The Anatomical Basis of Clinical Practice. Elsevier Health Sciences; 2016.
  • 3. Hall JE. Guyton and Hall Textbook of Medical Physiology. Philadelphia, PA: Elsevier; 2016.
  • Kaplan. USMLE Step 1 Lecture Notes 2016: Physiology. Kaplan Publishing; 2015.
  • Kaplan. USMLE Step 1 Anatomy Lecture Notes 2016. Kaplan Publishing; 2015.
  • Le T, Bhushan V,‎ Sochat M, Chavda Y, Zureick A. First Aid for the USMLE Step 1 2018. New York, NY: McGraw-Hill Medical; 2017.
  • Chung KW. Gross Anatomy. Baltimore, MD: Lippincott Williams & Wilkins; 2005.
last updated 07/02/2020
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