Liver Structure

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•  Dual blood supply to the liver and differences between sinusoids and capillaries

Hepatic Lobules

The liver is composed of smaller histological structures called lobules, which are roughly hexagonal in shape

  • Each lobule is surrounded by branches of the hepatic artery (provide oxygen) and the portal vein (provide nutrients)
  • These vessels drain into capillary-like structures called sinusoids, which exchange materials directly with the hepatocytes
  • The sinusoids drain into a central vein, which feeds deoxygenated blood into the hepatic vein
  • Hepatocytes also produce bile, which is transported by vessels called canaliculi to bile ducts, which surround the lobule

Structural Organisation of the Liver

liver lobule


Sinusoids are a type of small blood vessel found in the liver that perform a similar function to capillaries (material exchange)

  • Sinusoids have increased permeability, allowing larger molecules (e.g. plasma proteins) to enter and leave the bloodstream 

The increased permeability of sinusoids is important for liver function and is due to a number of structural features:

  • The surrounding diaphragm (basement membrane) is incomplete or discontinuous in sinusoids (but not in capillaries)
  • The endothelial layer contains large intercellular gaps and fewer tight junctions (allowing for the passage of larger molecules)

Structural Differences Between Sinusoids and Capillaries