Liver Flashcards
What are features of the liver
- The largest organ – 1.4kg
- Receives about 29% of cardiac output
- Performs essential metabolic and synthetic functions
- Split into right & left lobe – falciform ligament
What are features of the structure of the liver
- Lobules (~100,000) – 1mm histological divisions
- Acinus is the functional unit
- Hepatocytes in the parenchymal tissue
- It has a Portal Triad
- Central vein
What does the portal triad consist of
- Portal vein
- Hepatic artery
- Bile duct
How many sources of blood supply does the liver get
2 sources of blood supply
How many ml of blood does the liver get from the portal vein and the hepatic artery proper every minute respectively?
- 1100ml from portal vein
- 350ml from hepatic artery proper
What are Kupffer cells
Phagocytic cells
What do hepatocytes do
Hepatocytes (beige) absorb solutes & secrete materials as the blood passes
Where did sinusoids flow into
Sinusoids flow into the central vein
What do central veins merge into to become, and where do those blood vessels empty into
Central veins merge to become hepatic veins and empty into the inferior vena cava
What are the functions of hepatocytes
- Adjust circulating levels of nutrients through selective absorption and secretion
- Secretes bile into adjacent bile canaliculi
What is another name for Kupffer cells
another name for Kupffer cells reticuloendothelial cells
What are the functions of Kupffer cells
- engulf pathogens, cell debris & damaged/old RBCs
- antigen-presenting cells
- Store iron, some lipids and heavy metals (e.g. tin or mercury)
What is another name for stellate cells
another name for stellate cells is Ito cells
What type of cells are the main contributor to liver fibrosis
stellate cells
What are functions of the stellate cells
- Lie in the space of Disse
- Store vitamin A in lipid droplets in their cytoplasm
- Activated due to liver damage
What is the space of Disse
the area between the hepatocytes and sinusoids
What are the 3 general categories for liver function
- Metabolic regulation
- Haematological regulation
- Bile production & secretion
How many individual functions does the liver have
more than 200 individual functions
What is the liver’s function in relation to the composition of blood
- Regulates composition of blood
- extracts nutrients and toxins, stores excess nutrients so as to correct deficiencies if needed
What are the metabolic functions of the liver
- Carbohydrate metabolism
- Lipid metabolism
- Amino acid metabolism
What is toxic ammonia converted to
converted to harmless urea
What are the fat-soluble vitamins
vitamins A, D, E & K
What vitamins and minerals does the liver store
- Fat soluble vitamins (A, D, E & K)
- B12
- glycogen
- Copper
- Iron
What is the value that blood glucose is stabilised
- 90mg/dl
What circulating hormones regulate carbohydrate metabolism
insulin & glucagon
How do hepatocytes synthesise glucose during starvation and what is this process called
hepatocytes synthesise glucose from other carbohydrates or amino acids
Process is called: Gluconeogenesis
What do hepatocytes do when blood glucose increases
hepatocytes store blood glucose as glycogen or use to synthesise lipids
What do hepatocytes do when blood glucose decreases
hepatocytes break down glycogen reserves to produce blood glucose
What circulating levels does the liver regulate in respect to lipid metabolism
Liver regulates circulating levels of triglycerides, fatty acids and cholesterol
True or False: most lipids absorbed by the GI tract bypass the hepatic portal circulation
True
What does the liver removing or releasing lipids depend on
depends on circulating levels
What does the liver use cholesterol for
used for production of bile salts
What does the liver use amino acids for in respect to amino acid metabolism
Used to synthesise proteins
Give 3 examples of proteins that the liver synthesises
- Albumin
- Clotting factors
- Innate immunity proteins
What is albumin used for
– albumin for colloid osmotic pressure and transport of bilirubin
Give 3 examples of clotting factors that the liver synthesises
- fibrinogen
- plasminogen
- prothrombin
Give 2 examples of innate immunity proteins that the liver synthesises
- Complement proteins
- C-reactive protein
What are innate immunity proteins produced in the liver used for
Acute phase response
What is transamination
removal of an amino group from amino acids to make non-essential amino acids
What is deamination
Removal of an amino group when amino acids are converted to lipids or glucose for storage
What does deamination produce
Produces ammonia
What are haematological functions of the liver
- Phagocytosis & antigen-presenting
- Synthesis of plasma proteins
- Removal of circulating hormones
- Removal of antibodies
- Removal & storage of toxins
What are examples of the hormones removed and recycled by the liver
- Adrenalin
- Noradrenalin
- Insulin
- Thyroid hormones
- Steroid hormones
What are antibodies broken down to release by the liver
- Breaks them down to release amino acids
Where are lipid soluble toxins stored in and give an example of this
stores them in lipid deposits
Example is DDT
What happens to non-lipid soluble toxins
other toxins are broken down and excreted in bile
What cell produces bile
Made by hepatocytes
What makes up bile
- water
- bile salts
- bilirubin
- cholesterol
- ions
What is Bilirubin
Pigment derived from haemoglobin
What 2 things are bile salts essential for
- digestion (emulsification)
- absorption (micelle) of lipids
What do water and ions do in bile
- dilutes and buffers acidic chyme
Where is bile released into and via what passage
Released into duodenum via the common bile duct
What stimulates the gall bladder and sphincter of Oddi
CCK stimulates gall bladder and sphincter of Oddi
Where are bile salts reabsorbed
Reabsorbed in ileum
