Liver Physiology + Function Flashcards
75% blood supply to liver is from?
Portal vein
25% , blood supply to liver is from?
Proper hepatic artery
What brings nutrient rich blood into the liver?
Portal vein
What takes oxygenated blood into the liver?
Proper hepatic artery
What takes deoxygenated blood back to the vena cava?
Hepatic vein
Lobules are?
Collection of cells
Functional unit of the liver
Structure of hepatic lobule?
Hexagonal
Sinusoids define:
Small blood vessels between radiating rows of hepatocytes
Characteristics of sinusoids:
One cell thick
Nutrient exchange
Gaps that allow macromolecules to pass through
Hepatic lobule consists of?
Portal triad
Sinusoids
Central vein ( hepatic vein)
Hepatocyte
Kupffer cell
Portal triad
Bile duct
Portal vein
Hepatic artery
Kupffercells are?,
Type of tissue macrophage ( performs a lot of defence functions)
Canalinculi
Series of channels between cells
How does there billiary systems structure support function?
Two separate blood supplies and separation of blood from bile
Massive SA for exchange of molecules
Sinusoids structure allows exchange of large solutes
Kupffer cells form a protective barrier
Biliary system: Bile secreted by hepatocytes then…..
canalinculi —-> Collected by system of ducts (ductules)—->
Which drain into common hepatic duct (multiple bile duct)—-> to the common bile duct
Bile is secreted by?
Hepatocytes
Bile is a combination of?
Water, electrolytes, bilirubin, cholesterol and bile salts
What is bilirubin?
Toxic, yellow pigment; formed by the break down of haemoglobin
Where is bile stored?
Gallbladder
Bile is secreted where? After common bile duct
Duodenum
Duodenum is?
First part of small intestine; comes down from stomach
Function of bile
Fat digestion and absorption
Elimination of waste products especially bilirubin and cholesterol
Cholecystokinin CCK is?
A hormone that causes contraction of the gallbladder leading to ejection of bile into the duodenum
When is CCK released?
When it detects a lot of lipid rich food
One of the first signs of liver failure is? Why?
Jaundice—> due to the presence of bilirnebin in the body because it isn’t being handled properly by the liver
Enterohepatic circulation benefit
Gives liver first access to nutrients, toxins, medications from gut
What % of bile salts excreted in faeces?
5%
Functional unit of liver?
Liver lobule
Where are kupffer cells located?
Sinusoidal lining
Function of hepatocytes
Carry out most metabolic pathways
Function of pit cells
Natural killer plus specific to liver
Examples of blood clotting factors?
Fibrinogen
Prothrombin
other factors —> V, VI, IX, X, XII
What is essential ( vitamin)for formation of pro-thrombin and other factors?
Vitamin k
Where is vitamin k stored?
In the liver
Warfarin blocks the activity of what enzyme?
Epoxide reductase
How does warfarin have an anticoagulant effect on the blood?
Blocks epoxide reductase which means vitamin K stays in its oxidised form
Hence reduced form of Vitamin K produced = fewer clotting factors
Functions of liver
Bile production
storage of vitamin k / A/ D/ E/ B12+ carbohydrates and lipids+ iron (stored as ferritin)
Metabolism
Detoxification
Iron is stored as what in the liver?
Ferritin
Function of liver= metabolism. Give examples
Carbohydrates - glucagon and insulin
Lipids
Proteins - gluconeogenesis and deamination
Examples of cholesterol sources:
Dietary cholesterol —> Chylomicron remnants
De novo synthesis in liver
Cholesterol from extrahepatic tissue —> HDL
Chylomicron remnants define:
Fat molecules that get left over from digestion process
How are Chylomicron remnants transported into the liver?
Via portal vein
