Liver Function 2 Flashcards
Where does the liver get its blood supply from?
The hepatic portal vein and hepatic arteries
Where does the hepatic portal vein carry venous blood drained from?
Spleen, GI tract and its associated organs
What type of liver cells are parenchymal?
Hepatocytes - 80% liver volume
What live cells are non parenchymal?
Endothelial cells
Kupffer cells
Sinusoidal
What do bipotential stem cells form?
Ovalocytes form hepatocytes and cholangiocytes
What are the functions of the liver?
Synthesis
Breakdown
Storage
Immune system
What does the liver synthesise?
Amino acids
What does the liver metabolise?
Carbohydrates, proteins and lipids
In the first trimester foetus what is the liver the main site of?
Red blood cell production
What happens to bile synthesised by the liver?
Some bile drains directly into the duodenum, and some is stored in the gallbladder
What is the role of IGF-1 that is produced by the liver?
Important role in childhood growth and continues to have anabolic effects in adults
The liver is a major site of thrombopoetin production. What is the role of thrombopoietin?
Thrombopoietin is a glycoprotein hormone that regulates the production of platelets by the bone marrow
What is the liver involved in the breakdown of?
Breakdown of insulin and other hormones
Glucoronidates bilirubin, facilitating its excretion into bile
Toxic substances
Drug metabolism - sometimes results in toxication. Toxins are conjugated to avail excretion n bile or urine
Converts ammonia to urea (urea cycle)
How does the liver have immunological effects?
The reticuloendothelial system of the liver contains many immunologically active cells, acting as a sieve for antigens carried to it via the portal system
What is the role of albumin in blood serum?
It is the major osmolar component of blood serum
What hormone does the liver synthesise that is responsible for raising blood pressure where activated by renin?
Angiotensinogen
What are the features of bile?
Bitter tasting green / yellowish brown
Produced by the liver
Stored ad concentrated in the gallbladder
Discharged to duodenum
What is bilirubin?
Yellow breakdown product of haem metabolism
Excreted in bile and urine
What gives urine colour?
Urobilin
What gives faeces brown colour?
Stercobilin
What happens to bilirubin in heme?
Form larger ring porphyrins
What are bile acids?
Steroid acids found in the bile of mammals
Bile acids when conjugated with taurine or glycine in the liver form bile salts
Where are primary bile acids synthesised?
Liver
What are secondary bile acids a result of?
Bacterial actions in the colon
What account for 80% of organic compounds in bile?
Bile acids
Others include phospholipids and cholesterol
What are the functions of bile acids?
Amphipathic molecules with hydrophobic and hydrophilic regions
Form micelles: aid lipase to digest lipids
Move lipids near brush border - fat absorption
Eliminate cholesterol
Drives bile flow
Emulsify fat soluble vitamins (DEAK) to help absorption
Reduce bacterial floral in small intestine and biliary tract
What is the role of micelles?
Aid lipases to digest lipids
What eliminates cholesterol?
Bile salts
What emulsifies fat soluble vitamins (DEAK) to help absorption?
Bile salts
What is a major route of cholesterol metabolism?
Synthesis of bile acids
What percentage of bile acids are reabsorbed in ileum and recycled for further use? (Enterohepatic circulation)
95%
What route does bile travel?
Produced in the liver
Travel down left or right hepatic duct
Into common hepatic duct
Either flows into gallbladder to be stored via the cystic duct
Or flows down the common pancreatic duct
Flow into duodenum via the sphincter of Oddi
What are the intra-hepatic types of biliary disease?
PSC
PBC
Secondary biliary cirrhosis
What are the extra-hepatic types of liver disease?
Within lumen - stones
In wall of the lumen - stricture, cholangiocarcinoma
Extrinsic compression - pancreatic cancer
What is jaundice?
Hyperbilirubinaema manifest as yellow sclera or skin
Can be painful or painless
When does jaundice become apparent?
When serum bilirubin >2-3 x ULN
What are the causes of post hepatic jaundice?
(Conjugated hyperbillirubinaemia)
Blockage of flow of bile through liver to duodenum and / or gallbladder
Within bile lumen; stones, tumour
Within wall of lumen: stricture, PSC
Compression on the lumen; pancreatic cancer, hilar lymphadenopathy
What is ERCP?
Endoscopic retrograde cholangio-pancreatography
Therapeutic technique
Stone extraction
Stent insertion
Diagnosis
Tissue acquisition - bile brushings - spy glass
