Liver Physiology and Function Flashcards
What are the main aspects of structure which can affect the function of the live?
- Vascular System
- Biliary Tree
- 3D arrangement of liver cells.
In terms of blood supply, where is 75% of the blood supply coming in from?
The portal vein = this is ALL venous blood and is the blood which is returning from the GI tract.
GI TRACT = (spleen / pancreas / small intestine.)
In terms of blood supply, where is 25% of the blood supply coming in from?
The hepatic artery = this is ALL oxygenated blood.
Where does the portal vein feed into?
Portal vein feeds into the liver.
Where does the hepatic vein take blood to?
Takes blood back to the vena cava.
Where does blood from the central vein in the liver lobules drain into and what is the following step from this?
Drains into the hepatic vein and then, travels straight into the vena cava.
Where does the portal vein bring blood from?
Carries blood returning from the gastrointestinal tract.
NUTRIENT RICH BLOOD.
What does the gastrointestinal tract consist of?
Passes the gallbladder -> pancreas -> spleen -> liver.
What illness is associated with the portal vein?
Portal Hypertension = Increase in blood pressure.
In terms of histological organisation of the liver, what are the 4 main parts?
Parenchyma
Stroma
Bile Duct
Hepatic Artery
What is the parenchyma?
It is represented by the hepatocytes.
It is functional tissue of an organ.
What is the stroma?
Connective tissue of the stroma forms a MESHWORK.
This provides integrity for the hepatocytes and the sinusoids.
What is the bile duct?
This is where the bile duct is made in the cells and thus, allows the bile to be transported.
What is the hepatic artery?
This is the artery in which ALL the blood is oxygenated.
What. makes up the portal triad?
Bile duct
Portal vein
Hepatic Artery
Which two veins are found at the centre of the hepatic lobules?
Central Vein
Hepatic Vein
What is the difference between the blood entering the lobule and the blood leaving the lobule?
The blood entering the lobule is OXYGEN RICH but the blood leaving the lobule is OXYGEN POOR.
What is the main process which occurs in the hepatic lobule?
The blood enters the lobules via the branches of the portal vein and the hepatic artery.
Flows through the sinusoids.
Once the hepatocytes have cleared the blood, they exit the lobule via the central vein.
What is the purpose of the hepatocytes?
These remove toxic substances.
What are the 4 basic cells found in the liver?
Kupffer Cell
Liver Endothelial Cell
Stellate Fat Storing Cell
Hepatocytes Cell
What is the purpose of the Kupffer cells?
These cells line the sinusoids.
They have phagocytic activity which REMOVE aged / damaged RBC’s / viruses / immune complexes.
What is the purpose of the Stellate fat storing cells?
These store the majority of vitamin A.
What is the purpose of the liver endothelial cells?
These form a FENESTRA which allows efficient flow.
These can absorb solutes from the plasma and secrete material into it.
What is the purpose of the hepatocytes?
These perform MOST metabolic functions.
What is the percentage of hepatocytes compared to Kupffer cells?
Hepatocytes = 60%
Kupffer Cells = 30%
Due to whose function does less than 1% of macrophages enter the systemic circulation?
Kupffer Cells.
What is the purpose of sinusoids?
These have LARGE openings which allows the passage of solutes.
What is the biliary system?
These are organs and ducts which make / store bile.
What is bile?
Fluids made in the liver which help DIGEST fat.
Name the key parts of the biliary system.
Bile secreted by hepatocytes. Travels through: - Cananlinculi - Ductules - Hepatic Ducts - Common Bile Duct
How does the surface area of the biliary system aid the function?
There is a massive surface area which allows for the exchange of molecules.
What are the two main components of bile?
Cholic Acid
Chenodeoxycholic Acid
Where is bile secreted from and into where?
Secreted by the hepatocytes and secreted into the duodenum.
Where is bile usually stored in?
Stored in the gallbladder.
How are bile salts formed?
This is when cholic acid and chenodeoxycholic acid are conjugated with GLYCINE and TAURINE.
What is the purpose of the spinchter of odii?
Entry of bile into the duodenum is controlled by the sphincter.
It is a smooth muscle.
What are the 2 main functions of bile?
Digests fat and absorbs fat too.
Eliminates waste products.
What are the 2 waste products produced by bile?
Bilirubin
Cholesterol
What is bilirubin?
It is a yellow pigment which has been formed from the breakdown of haemoglobin.
How is bilirubin excreted and eliminated from the body?
It is excreted from the body by secretion into bile and then, is eliminated into the faeces.
What is Cholecystokinin?
It is also known as CCK.
This is a peptide hormone which causes the contraction of the gallbladder.
This contraction leads to the ejection of bile into the duodenum.
What does CCK aid with?
It facilitates digestion within the small intestine.
Where is CCK secreted from?
It is secreted from the mucosal epithelial cells.
What is enterohepatic circulation of bile?
This is the circulation of biliary acids / bilirubin / drugs from LIVER TO BILE.
This enters the small intestine and is absorbed by the enterocyte.
From the enterocyte, it’s transported back to the liver.
Which part of the small intestine does it enter?
It enters the interstitial lumen.