The liver: structure and function Flashcards
What are the functions of the liver?
- metabolic
- biotransformation (drugs, lipophilicity)
- bile production
- bilirubin secretion
- Storage (glycogen)
What are the non-parenchymal cells of the liver?
- Kupffer cells
- Sinusoidal endothelial cells
- Hepatic stellate cells (collagen synthesis)
What are the two vessels that supply the liver?
hepatic artery and portal vein
Where does the common hepatic artery branch from?
The celiac artery
What artery supplies the gallbladder?
Cystic arteries
Which two veins come together to make up the portal vein?
splenic vein and superior mesenteric vein
Which strutures make up the beginning of the biliary system?
Canals of Hering
Lymph–Where does it form? Where does it drain to?
Lymph forms in the space of disse. It drains to the lymph nodes of the hilum and vena cava
What keeps the liver in place?
Coronary ligaments
Right and left triangular ligaments
Falciform ligaments
Hepatoduodenal ligament
What is contained in the hepatoduodenal ligament?
- hepatic artery
- Portal vein
- Common bile duct
- Lymphatic vessels
- Nerves
What direction does blood flow? What direction does bile flow?
Blood: From portal triad to central vein.
Bile flows in the opposite direction
What does the basal surface of the hepatocyte face?
Sinusoidal space
What does the apical surface of the hepatocyte face?
Other hepatocytes cells
What does the lateral surface
The bile canaliculi
Describe the breakdown of bilirubin
HgB–>Heme–>Biliverdin–>bilirubin. It’s then transported through the blood by albumin. Taken up by hepatocytes. Conjugated by UDP-glucuronosyltransferase to be made water soluble. Excreted through bile ducts
What are the components of bile?
- Conjugated bilirubin
- Cholesterol, phospholipids
- Bile salts
- Water, electrolytes
What does bilirubin become in the bowel?
urobilinogen. Can be resorbed into the blood stream.
Why does your urine become dark with bile obstruction?
high levels of conjugated bilirubin and urobilinogen excreted in the kidneys
What are the three categoric causes of jaundice?
- Pre-hepatic
- Hepatic
- Post-hepatic
Give examples of a pre-hepatic cause of jaundice
hemolysis
Excess production of bilirubin
Give examples of hepatic causes of jaundice
Liver disease. Either cannot process the bilirubin or the UDP-glucuronyltransferase is not working.
Give an example of posthepatic jaundice
Obstruction of bile duct
What causes decreased activity of UDP-glucuronosyltransferase?
Congenital (Gilbert’s/Crigler-Najjar) or drugs
Does liver cell damage cause an increase in conjugated or unconjugated bilirubin?
Both: decreases uptake of bilirubin and decreases excretion of conjugated
What proteins are NOT made by the liver?
IgGs
What imaging studies would show liver pathology?
Ultrasound and CT scan
What are physical exam findings in liver disease?
- Jaundice
- Hepatomegaly
- Splenomegaly
- Spider angiomas
- Edema
- Ascites
- Asterixis
When is AST elevated?
Dying cells=enzyme leakage
When is ALT elevated?
virus/toxins
What is alkaline phosphatase?
Liver isozyme
How is gamma-GT, released?
Biliary epithelium
If you see elevated AST and ALT, you would think:
Hepatic cause of jaundice. Might see damage to liver (cirrhosis)
If you see elevated AP + gamma-GT, you would think…
Biliary tract injury. Would also see an enlarged bile duct.
