4 Liver function Flashcards
What can compromise normal liver function?
Active metabolites that attack DNA Chronic liver damage Persistent liver enlargement Congestive agents Agents which provoke haemorrhagic necrosis
What are he main metabolic functions of the liver?
Storage of glycogen, regulation of homeostasis
Synthesis and oxidation of fatty acids and formation of ketone bodies
Oxidation of amino acids and formation of urea
Modification of steroids, hormones, xenobiotics
Production and recycling of bile salts
Maintains energy supply to body tissues under different healthy and disease states e.g. The brain needs a constant supply
To a lesser extent, synthesis of serum proteins, bacteria etc.
Storage of iron, removal of blood cells, toxins etc., storage of vitamins, reservoir of blood, storage of heat.
What can the liver do to repair mild damage?
Division of mature hepatocytes
Oval cells at the edge of portal tracts can divide and differentiate, restoring liver architecture
True or false?
The majority of the livers energy demand is met by the oxidation of glucose?
False
The liver doesn’t use much glucose for energy
True or false
During fasting conditions the brain is able to oxidise fatty acids to derive energy.
False
The brain cannot oxidise fatty acids to derive energy.
True or false
Oxidation of free fatty acids during fasting conditions provides substrates for gluconeogenesis.
False
FFA cannot be converted to glucose
True or false
Excess amino acids provide substrates for fatty acid synthesis during well fed conditions
True
True or false
Amino acids provide substrates for gluconeogenesis during fasting conditions
True
Amino acids from muscle protein can be used for gluconeogenesis, hence muscle wastage in starvation.
What are the key cycles cooperating between tissues in metabolic processes?
Cori cycle
Glucose : alanine cycle
Glucose : fatty acid cycle
What is the function of the cori cycle?
To recycle glucose used by muscle, released in the form of lactate
Draw the glucose-fatty acid cycle
What does it explain?
Oxidation of fatty acids causing heightened levels of citrate and NADH causes glucose oxidation to be suppressed in muscles for use by the brain.
In the obese, high fat consumption is accompanied by high glucose consumption causing a buildup of glucose in the system and therefore insulin resistance / type 2 diabetes
In the well fed state dietary triacylglycerol is packaged into ____
Insulin is secreted
FFAs produced by the liver are packaged into ____ particles
Insulin promotes FFA hydrolysis and uptake into adipose by activating ______
Glucose uptake into muscle from _____ translocation
Chylomicrons
VLDL
Lipoprotein lipase
GLUT4
High ____ concentrations produced by the oxidation of glucose will drive fatty acid synthesis through ______ effects which promote the synthesis if _______ from acetyl coA
This in yarn serves to inhibit _-oxidation by inhibiting _______ on the mitochondrial membrane, reducing the ______ of fatty acids.
High citrate concentrations produced by the oxidation of glucose will drive fatty acid synthesis through allosteric effects which promote the synthesis if Malonyl-coA from acetyl coA
This in yarn serves to inhibit beta oxidation by inhibiting CPT-1 on the mitochondrial membrane, reducing the oxidation of fatty acids.
In the fasting state, what is released when muscle oxidises protein?
What happens to these products?
Alanine and glutamine
Alanine goes to the liver and is converted to pyruvate
Glutamine is transaminated in the enterocytes of the gut into alpha-keto glutarate before entering the TCa cycle
The liver of a this person is glycogenic, glycolytic and lipogenic
Are they well fed or starved?
Well fed
