What the Liver does Flashcards
What is “ischaemia”?
A restriction in blood supply to tissues, causing oxygen and glucose starvation
What minerals / ions does the liver store?
Iron Copper Vitamin A Vitamin D Vitamin B12
What nutrients does the liver metabolise?
Carbohydrates
Proteins
Lipids
What two substances does the liver excrete?
Bile salts
Bilirubin
In the centre of a liver lobule, which vessel is found?
Hepatic venule
In the outer region of the liver lobule, which two vessels can be found?
The branch of:
- The hepatic portal vein
- The hepatic artery
The inner region of the liver lobule is periportal or perivenous? What does it mean?
Perivenous - low oxygen
The outer region of the liver lobule is periportal or perivenous? What does it mean?
Periportal - high oxygen
Which region of the liver lobule will suffer from damage first, and why?
The perivenous region, because it is already a low oxygen environment
What does BMR stand for and what is it?
Basal Metabolic Rate, accounts for 60-75% of daily calorie expenditure
Insulin and Glucagon is released by which cells?
Beta cells of the Iselets of Langerhan in Pancreas (Insulin)
Alpha cells of the Iselets of Langerhan in Pancreas (Glucagon)
In a liver lobule, blood moves from the peri___ region to the peri____ region…
Periportal to perivenous
What are the three classes of amino acids?
Essential
Non-essential
Semi-essential
What is an essential amino acid?
An amino acid which cannot be synthesised and must be taken in the diet
What is a non-essential amino acid?
Amino acids which can be synthesised in the body by transamination. Not required to be taken in by the diet.
What is a semi-essential amino acid?
Amino acids which become essential under conditions of metabolic stress
What is the transamination of amino acids?
The transfer of an amino group to a keto-acid to form a new amino acid
What are the three main transaminase enzymes?
ALT
AST
Glutamate aminotransferase
What does an increase in AST/ALT levels suggest?
Liver damage
What does an increase in ALP suggest?
Possible cholestasis / cirrohosis
What does an increase in GGT suggest?
Cholestasis
What does an increase in PT (prothrombin) suggest?
Possible liver damage
What is deamination?
The removal of an amino group from an amino acid or other compound
It was previously thought that Urea was completely removed, however it is now believed ?% of Urea is recycled
25%
25% of Urea is re-cycled, but how does this occur?
Urea synthesised in the liver, can go back into the intestine, whereby bacteria breaks down Urea via Bacterial Urease into ammonia, then ammonia into amino acids by Bacterial synthesis
What are the four sub stages of phase one / first pass metabolism?
Oxidation
Hydrolysis
Hydroxylation
Deamination
What enzyme is responsible for first pass metabolism?
Cytochrome P450
What is Phase Two Metabolism also known as?
Detoxifiation / Conjugation Pathway
What happens during Phase Two metabolism?
The liver cells add another substance (e.g. cysteine, glycine, or S) to a drug to render it less harmful
How many units are adults permitted to drink usually per week?
14 units per week