Alimentary Systems 2 - Liver Flashcards
Where is the liver located?
- Behind the ribcage, but below the diaphragm
- Mainly on the right of the body
- Also in the upper left quartile
Describe the basic gross anatomy of the anterior liver surface
- Right lobe is the largest, left lobe is smaller. These are the only lobes visible in an anterior view
- Right and left separated by the falciform ligament, which becomes the ligamentum teres
- Coronary ligament above the right lobe
- Left triangular ligament above the left lobe
Describe the basic gross anatomy of the posterior liver surface
- Caudate lobe can be seen between the left and the right lobe, superior
- Quadrate lobe can be seen between the right and left lobe, inferior
- Gallbladder is seen between the quadrate love and the right lobe
- IVC and left hepatic vein at the top
Describe the couinaud classification
- 8 functionally independent segments, labelled in a clockwise direction (1-8)
- Centrally there is the portal vein, hepatic artery and bile duct
- Peripherally hepatic vein
Describe the blood supply of the liver
- Rich blood supply (25% of resting cardiac output)
- Dual blood supply (20% arterial from hepatic artery left/right)
- Hepatic portal vein (80%venous blood)
- Drains into the inferior vena cava
What is the purpose of the dual blood supply?
- Hepatic portal vein (nutrients from the stomach are delivered to be processed)
- Hepatic artery (delivers oxygenated blood)
How is the liver divided morphologically?
- Lobules
- A lobule contains a portal tract/triad containing the branch of the hepatic portal vein, hepatic artery, and a bile duct.
- 6 triads in one lobule
- Interlobular veins in the centre drain to hepatic vein
- Bile drains the opposite direction to blood (blood to centre, bile to triad)
Describe the functional division of the liver?
- Acinis
- Blood flow (diamond shape joining two interlobular veins)
- Bile flow (from centre to portal tract via canaliculus)
- Zone 3 is furthest from the portal tract
- Zone 1 is closed to the portal tract
- Zone 2 is in the middle
List the functions of the liver
- Bodys kitchen
- Biosynthesis
- Digestion
- Energy/metabolism
- Degradation
- Detoxification
List the cell types in the liver and their proportion/location.
- 80% of the cells are hepatocytes
- Endothelial cells line blood vessels and sinusoids
- Cholangiocytes line biliary structures
- Kupffer cells are phagocytes in the sinusoid
- Hepatic stellate cells store vitamin A, and are activated to be fibrogenic
Compare the structure of hepatocytes, hepatic stellate cells and kupffer cells
- Flattened, dense cell nuclei in the sinusoid may be Kupffer cells or stellate cells
- Hepatocytes are large with pale and rounded nuclei
Describe the arrangement of hepatocytes
Radiate from a central vein in sheets (cords)
Describe the function of sinusoidal endothelial cells
- Fenestrated
- Allows lipid and other large molecules to move to and from hepatocytes
List the functions of kupffer cells
- Phagocytosis
- Secretion of cytokines that promote HSC activation
How long does it take for stored liver glycogen to be used up?
It will be used in a 24 hour fast