lecture 3 - liver function tests Flashcards
what does the vein carry
deoxygenated blood
what is the main process in the liver
- uptake(portal vein)
- metabolism
- supply (vena cava)
- detoxification
- excretion (bile duct -> intestine)
give 3 functions of the liver
The uptake of nutrients delivered from the digestive tract via the portal vein
The detoxification of harmful compounds by biotransformation
Fighting infections (Kuppfer cells-macrophages)
what are three types of metabolism
carbohydrate
lipid
amino acid and protein
can the liver be regenerated?
yes, within 70 days
only organ that can
what happens during carbohydrate metabolism
- takes up glucose from plasma
- convert the to glucose 6-phosphate
- stored as glycogen or fatty acid
GLYCOGENESIS
what happens when there’s a major decline of blood glucose
secretion of glucose
what does breaking down excess amino acids do
release nitrogen
is converted to urea and transported to the kidneys
what is liver the site of
synthesis and degradation of most protein and peptides in the blood plasma
what is the deamination process (products)
amino acids -> ammonia -> acetyl coA/glucose/ketone
what is the most abundant protein in the blood and where is it made
albumin
liver
what does albumin do
maintain osmotic pressure
binds drugs
what is biotransformation
a metabolic process that helps to facilitate the excretion of both outside and inside substances.
examples that metabolised by biotransformation
drugs, ethanol and other foreign substances (xenobiotics)
what are aminotransferases
enzymes that loads amino acids onto tRNAs
what are biomarkers
A defined characteristic that is measured as an indicator of normal biological processes, pathogenic processes or responses to an exposure or intervention
what is ALT
alanine aminotransferase
what is AST
aspartate aminotransferase
when are AST and ALT released
when there is a damaged hepatocyte
what are ALT and AT indicators of
hepatocellular damage
what are the limitations of ALT and AST
not suitable for chronic conditions as may appear normal
AST is non specific for liver disease - can be found in heart/kidney
what is prothrombin time
time taken for blood to clot
what are the limitations of prothrombin time
unreliable in patients taking anti-coagulants
indicator of severe live disease or cirrhosis (scarring)
what is bilirubin
the yellow breakdown product of RBC breakdown
how is bilirubin excreted
bile and urine
what is bilirubin responsible for
the yellow colour of bruises,
yellow colour of urine, brown colour of feces
what makes bilirubin soluble
liver enzymes convert unconjugated bilirubin to conjugated bilirubin
what causes jaundice
increased bilirubin
what is another name of conjugated bilirubin
direct bilirubin
what is another name for unconjugated bilirubin
indirect bilirubin
what happens when conjugated bilirubin is normal
then the problem is an excess unconjugated bilirubin, and the location of the problem is upstream of bilirubin conjugation in the liver
what happens when conjugated bilirubin is elevated
then the liver is conjugating bilirubin normally but is not able to excrete
what is ALP and what does it do
alkaline phosphatase
removes phosphate groups from proteins
what are the limitations of ALP
bone growth disorders elevate ALP
bone cancers can also raise ALP
how is vitamin synthesised
- Cholesterol precursor activated by UV-light in the skin
- This is inactive
- Requires hydroxylation by liver and then kidney enzymes
what is iron stored as
ferritin
what is ferritin
multi-subunit protein
binds Fe atoms
what does excess Fe do
its toxic to the liver
what is haemochromatosis caused by
a genetic mutation in the HFE gene
what does excess iron do to the liver
impairs liver function
chronic condition
what tests do you run for haemochromatosis
raised serum ferritin
genetic testing
what its Wilsons disease
condition that impairs removal of excess copper
you got this!!
how can soluble drugs be removed
in its original form by the kidneys
how are insoluble drugs removed
can have to be modified from soluble to insoluble form so that they can be removed by the liver.
