Liver Function Flashcards
Blood is supplied to the liver by the _________ _________ and hepatic portal vein.
Hepatic artery
______ flows from hepatocytes, via canaliculi and ductules, to form hepatic ducts.
Bile
The liver is organised into functional units are called ___________.
Lobules
What shape is each hepatic lobule?
Hexagon
____________ are arranged into irregular, branching, interconnecting plates around the hepatic vein.
Hepatocytes
Portal ________ lie at each ‘corner’ of the liver lobule.
Triads
How do hepatocytes generate energy?
Oxidative phosphorylation and fatty acid phosphorylation
____________ contain proteolytic enzymes.
Lysosomes
What is the role of hepatic endoplasmic reticulum?
Bile acid synthesis and drug metabolism
List two functions of the liver.
Bilirubin conjugation and protein synthesis
List three functions of the Golgi complex.
VLDL production
Protein glycosylation
Albumin secretion
Gluconeogenesis, glycogenesis and glycogenolysis, together with _________ ______ metabolism are major liver functions.
Fatty acid
Name three substances that are detoxified and/or excreted by the liver.
Cholesterol, amino acid, and toxins
Red cells are removed from the circulation by the ______________ _________ of the liver and spleen.
Reticuloendothelial system
True or false: unconjugated bilirubin is insoluble.
True
Unconjugated bilirubin is transported while bound to _________.
Albumin
Unconjugated bilirubin can cross the blood-brain barrier, and is therefore potentially _________.
Toxic
If not bound to albumin, unconjugated bilirubin is ______-soluble
Lipid
Bilirubin is taken up by ____________ and conjugated (in ER) to mono- and diglucuronides.
Hepatocytes
Normal bile is comprised of 25% _______________ and 75% diglucuronides.
Monoglucuronides
Conjugated bilirubin is soluble, and is converted to _______________ by GIT bacteria.
Urobilinogen
True or false: all urobilinogen is reabsorbed.
False
Most urobilinogen is oxidised in gut to a brown pigment (______________) and excreted.
Stercobilin
Unconjugated bilirubin is not filtered by the ______________.
Glomeruli
If conjugated bilirubin is found in urine, this reflects an increase in plasma concentration, and is ________________.
Pathological
___________ results when bilirubin > 50µmol/.
Jaundice
Pre-hepatic jaundice is caused by _____________.
Haemolysis
___________ jaundice, arises from failure of the conjugating mechanism, e.g., in the case of drugs, prematurity, hepatitis, etc..
Hepatic
Post-hepatic jaundice occurs when the __________ ________ is blocked. such as with gall stones.
Biliary tract
List three causes of unconjugated hyperbilirubinaemia.
Haemolytic disease of the newborn, increased bilirubin production, and due to low activity of conjugating enzymes at birth
HDN carries a risk of ___________.
Kernicterus
____________ _________________ is caused by leakage of bilirubin from hepatocytes or biliary system into the blood stream.
Conjugated hyperbilirubinaemia
In conjugated hyperbilirubinaemia, bilirubin may be excreted in urine, forming a deep orange-_________ colour).
Brown
Outline the principle of the chemical Diazo reaction.
Diazotised sulphanilic acid reacts with bilirubin to produce two azodipyroles. The reaction can be ‘accelerated’ to facilitate the reaction of unconjugated (indirect) bilirubin.
Total bilirubin = indirect + direct bilirubin
Bilirubin in infants can be measured directly by spectrophotometry, with no interference from ___________ and other pigments.
Carotene
Fasting, morning sample is preferred to avoid ___________.
Lipaemia
Bilirubin samples must be protected from ________.
Light
When is fractionation indicated?
In neonates
Obstruction in the biliary tract is termed ‘______________’.
Cholestasis
Acute hepatocellular damage causes changes to ________________.
Aminotransferases
Chronic liver disease can cause a decrease in albumin and ___________ time.
Prothrombin
Both aspartate aminotransferase and alanine aminotransferase catalyse the interconversion of amino acids to 2-oxo-acids, by transferring _______ groups.
Amine
The transaminase reaction is coupled to another reaction, such as ________ _____________, or lactate dehydrogenase.
Malate dehydrogenase
Which enzyme has a reference range of 0-40 U/L?
Aspartate aminotransferase
Which enzyme has a reference range of 0-45 U/L?
Alanine aminotransferase
_________ consumption is measured as a change in absorption at 339 (340) nm, over several minutes.
NADH
The difference in absorbance per minute is equal to NADH oxidised, and synonymous with __________ ________.
Enzyme activity
Describe alkaline phosphatase.
Catalyses the hydrolysis of many substrates. Distributed widely, in the bone, placenta, kidney, etc.. Most serum ALP is derived from the liver and bone. Several isoenzymes exist, and they can be identified by electrophoresis. Increased in children and adolescents, but lower in adults. Raised especially in cholestatic liver disease, with a moderate or absent elevation in infectious hepatitis. 4-nitrophenyl is converted to 4-nitrophenoxide. Reference range is 35-104 U/L
A peptidase, that catalyses the hydrolytic cleavage of peptides to form amino acids. Derived mostly from the liver. Elevated in all forms of liver disease. More sensitive than ALP and aminotransferases. References range for a female is 6-50 U/L, and for a male, 11-85 U/L is normal.
To which enzyme does the passage refer?
y-glutamyl transferase
_______________ is a feature of chronic liver disease, and severe acute liver disease.
Hypoalbuminaemia
a-fetoprotein is used to investigate ____________ _____________.
Hepatocellular carcinoma
What does prothrombin time measure?
Coagulation factors that are made by the liver
All ___________ assays require a sufficient spectrophotometer, and standardisation and temperature are important.
Enzyme
True or false: hepatic failure is a medical emergency.
True
List two potential causes of hepatic failure.
Electrolyte imbalances and severe metabolic acid-base disorders
The liver is a common site for _________ _________.
Tumour metastasis
Wilson’s disease pertains to abnormal ________ metabolism.
Copper
