Anatomy - Liver Flashcards
Situation of the liver
- under the diaphragm
- right upper quadrant, most of right hypochondriac region and epigastric
- Attatched to diaphragm by falciform, coronary and triangular (R and L) ligaments
- lesser omentum attatches liver to stomach, cont with traingular ligament
What are the surfaces of the liver
Diaphragmatic (front)
Visceral (posteroinferior)
What is the visceral surface related to
- abdominal oesophagus
- fundus and body of stomach
- lesser omentum
- gallbladder
- sup duodenum
- transverse colon
- right kidney and its adrenal gland
Lobes of liver
based on blood supply and bile drainage there are 2; right and left
separated by falciform ligament
Also have 2 minor caudate (sup) and quadrate (inf) lobes (both mainly in right lobe)
Segments in terms of blood supply
8 segments that can be mapped onto the lobes
Blood supply to the liver
Very rich blood supply from;
hepatic artery
portal vein
Blood supply; hepatic artery
Branch of coeliac trunk
divides into left and right branches to supply left and right lobes
30% of blood supply to liver
Blood supply; portal vein
Carries venous blood rich with products of digestion from the GI tract, stomach, spleen and pancreas
70% of blood supply to liver
Divides into left and right for the separate lobes
How is the hepatic portal vein formed
From the union of the superior mesenteric vein and the splenic vein
Venous drainage
Via hepatic vein
Central vein from each lobule drains into interlobular vein, which then drains into the hepatic vein
Lymph drainage of liver; deep vessels
Deep vessels come together at porta hepatis and end in the hepatic lymph nodes scattered along the hepatic vessels
These drain into the coeliac lymph nodes to drain into thoracic duct
SOME deep lymph vessels follow hepatic veins through diaphragm and end in phrenic lymph nodes
Lymph drainage; superficial vessels
Follow same drainage as the deep but also can darin into mediastinal lymph nodes
Nerve supply to liver
Recieves both parasymp and symp innervation.
Nerve fibres reach lier via hepatic plexus, derived from coeliac plexusAlso recieves para from right phrenic nerve and R and L vagi
Hepatic nerves follow blood supply and enter at porta hepatis
What is the porta hepatis
Deep fissure on visceral surface (inf) contains - hepatic artery - portal vein - hepatic nerve plexus - hepatic ducts (out) - lymph vessels
Describing structural units of liver; classic lobule
Each lobule is a hexagon with central vein in the centre and a portal triad at each of its corners (6)
What is a portal triad
consists of
- a branch of hepatic artery
- a brach of portal vein
- a bile duct
Describing structural units of liver; portal lobule
Views the liver as being made up of a series of triangles with portal triad at the centre and a central vein at each corner (3)
Emphasises EXOCRINE function
Describing structural units of liver; acinus
Elliptical (circular) unit with portal triad at centre and central vein at each pole (2)
Emphasises ENDOCRINE function
Three zones of acinus
More accurate descipt of functional unit of liver as reflects gradient of metabolic activity
- periportal zone (zone 1)
- midzone (zone 2)
- centrilobular zone (zone 3)
Periportal zone
Most oxygenated blood found here centre around portal triad adjacent to portal canal recieves most blood from hepatic artery and portal vein most susceptible to damge from toxins most metabolic activity happens here
Centrilobular zone
Furthest away from portal triad
closest to central vein
most susceptible to ischaemic damage (eg. heart failure)
Types of cell present in liver
Hepatocytes
Kupffer cells
Haematopoietic cells
Perisinusoidal cells
Hepatocytes
Arranged in ‘cords’ (lines) that radiate out from the central vein.
Large, eosinophilic cells with round nuclei. More than half are tetraploid (4x no of normal chromosomes)
Network of capillaries (sinusoids) between them
Kupffer cells
Part of the monocyte-macrophage system
phagocytose old erythrocytes and other cell debris from circulation
Line the sinusoids capillaries
