B3 Physiology of Liver and Spleen Flashcards
What does the spleen primarily do?
Filters the blood for damaged RBCs
What are primary liver cells called?
Hepatocytes
What is the role of hepatocytes?
Remove toxic substances (including alcohol) from the blood
How do toxic substances leave the liver?
Out of the lobules via the hepatic venule
What is the hepatic venule?
The central vein of all the lobules
Why does the blood leaving the lobule contain low levels of oxygen?
Hepatocytes along the sinusoids have used up much of the available oxygen
What are sinusoids?
Little sinuses that the carry blood from the hepatic portal vein and hepatic artery, through hepatocytes where it will eventually reach the hepatic venule
What is the periportal zone I?
The region of liver lobules nearest to the entering vascular supply
What is clinically important about the periportal zone I?
Least sensitive to ischaemic injury but very susceptible to viral hepatitis
What region will have the poorest oxygenation and will be most affected in ischaemia?
Centrilobular Zone III
What are zone I hepatocytes specialised for?
Oxidative liver functions including:
Gluconeogenesis
Beta oxidation of fatty acids
Cholesterol synthesis
What are zone III cells important for?
Glycolysis
Ketogenesis
Lipogenesis
Which cells would be most specialised for cytochrome P450 based drug detoxification?
Zone III
What is the consequence of cholestasis?
Bile can’t get out of the liver
What is the major protein of the liver?
Albumin
What is hypoalbuminaemia?
A feature of chronic liver disease though can also occur in severe acute liver damage
What is a major enzyme in amino acid deamination?
Glutamate dehydrogenase
What does the liver do with ammonia?
Via the portal vein, it can be incorporated into amino acids
What is the liver’s effect on glycogen synthesis?
Increases it
What is glucagon’s effect on gluconeogenesis?
Increases it
What is phase 1 of drug metabolism?
Leads to polar, more reactive chemicals.
What is phase 2 conjugation
Leads to more polar but less reactive chemicals
What are the main points in aspirin metabolism?
Attaching hydroxyl group to aspirin and conjugation
What is the most common cause of liver dysfunction in the UK?
Non-alcoholic fatty liver disease (NAFLD)
What does NADH to when it accumulates?
Conversion from pyruvate to lactate instead of glucose
True or false? People who have drunk a lot of alcohol can become hypoglycaemic?
True- trying to produce glucose via gluconeogenesis but NADH drives pyruvate conversion to lactate
