Liver BASICS Flashcards
What are the main functions of the liver?
Metabolic/Catabolic functions: make carb, fats and proteins
Secretory and excretory functions:make and release bile and waste products
Detoxification and immunological functions: break down ingested pathogen and process drugs
What are the functions of bile?
Emulsification and absorption of fat: increase SA for lipase
Cholesterol homeostasis: excrete XS
Toxin excretion: endogenous (bilirubin) and exogenous (drugs)
What seperates the two lobes of the liver?
Falciform ligament
What are the two lobes of the liver?
Right and left
What are the main perfusing vessels to the liver?
Hepatic artery 20% and hepatic portal vein 80%
How can the liver be further separated?
Into discrete segments (8) with their own anatomical borders and independent blood supply and bile drainage so can have severe damage in one part of liver w/o affecting rest
What is a hepatic lobule?
Structural hexagonal unit of liver tissue
What is found at each corner of the hepatic lobule hexagon?
Portal triad
What is a portal triad?
It has 3 conduit vessels/ducts: hepatic portal vein branch, hepatic artery branch, bile duct
What is found at the centre of the liver lobule?
Central vein that collects blood draining from hepatic sinusoids to return it to the systemic venous system via the hepatic veins
What are found within the hepatic lobule?
Rows of hepatocytes with sinusoid facing side and bile canaliculi facing side
What does the branch of the hepatic portal vein in the portal triad contain?
BC its coming from venous blood in GI organs and spleen, has raw nutrients, bacteria, toxins, waste products
What do the hepatocytes in the hepatic lobule do?
Process nutrients, detoxify the blood and excrete waste substances before the blood returns to the circulation
What does the branch of the hepatic portal vein in the portal triad contain?
Oxygen rich blood into the liver tissue to help support the hepatocyte high energy demands
What does the bile ducts do?
Bile made from hepatocytes drain into tiny canals called bile canaliculi and eventually coalesce with the cholangiocyte lined bile ducts located around the lobule perimeter
Where does bile and blood flow towards in the hepatic lobule?
Blood flow toward centre
Bile flow toward perimeter
What is a hepatic acinus?
Functional unit of liver that is harder to define anatomically than a hepatic lobule
What is a hepatic acinus made up of?
Two adjacent 1/6 lobules that share 2 portal triads and extend as far into the lobule as central veins
How much oxygen and toxin do the three zones of the acinus recieve?
Zone 1 - o2 high toxin risk high
zone 2 - o2 medium toxin risk medium
zone 3 - o2 risk low toxin risk low
What are the 5 cell types in the liver?
Endothelial cells Kuppfer cells Hepatic stellate cells Hepatocyte Cholangiocyte
What do endothelial cells look like?
No basement mambrane, many fenestrations, discontinuous endothelium, very leaky
What do endothelial cells do?
Allow transfer of lipids/proteins/carbs
What do kuppfer cells look like
They are sinusoidal macrophage cells that are stellate shaped and attached to endothelial cells
What do Kuppfer cells do?
Eliminate and detoxify substances arriving into liver form portal circulation - phagocytosis
What percentage of the liver cell population is kuppfer cells?
15%
What do hepatic stellate cells look like?
They exist in a quiescent (dormant) state and become activated (fibroblasts) in response to liver damage
What do hepatic stellate cells do?
Store vit. A in liver cytosolic droplets
Proliferate, chemotactic and deposit collagen in the extracellular matrix
What do hepatocytes look like?
Cubical and approx 80% of mass
What do hepatocytes do?
Synthesise many things inc. albumin, clotting products/factors and bile salts
Drug metabolsim
Where do hepatocytes receive nutrients and building blocks from?
Sinusoid
What do cholangiocytes do?
Secrete bicarb and water to form bile
What do peroxizomes do?
Key roles in detoxification, waste management, cholesterol and bile synthesis
What structures are found in hepatocytes?
Nucleus Golgi apparatus Rough ER Mitochondria Smooth ER Cytoplasmic enzymes Glycogen Lysozomes Peroxizomes
