Laboratory Medicine Flashcards
(54 cards)
What are the 5 main electrolytes in body fluid?
Na+, Cl-, Mg2+, Ca2+, K+
What are the 5 functions of hepatocytes?
1) Drug and toxin metabolism
2) Aid digestion via biliary system
3) Protein synthesis and secretion
4) Energy storage (glycogen)
5) Transformation and clearance
How can acetaminophen cause liver necrosis?
Liver produces a toxic metabolite of APAP –> too much leads to necrosis
What is the main job of the liver?
Take insoluble compounds and make soluble for excretion
Pyridoxal phosphate (AKA Vitamin B6) plays a role in what types of reaction in the liver?
It is a coenzyme of all transamination reactions
What is the function of transaminases?
Transfer amine groups to allow for excretion
Is ALT or AST more specific for liver injury and why?
ALT is more specific because found in cytosol of liver - AST is found in both cytosol and mitochondria of liver along with many other organs
What four things cause elevated AST/ALT?
Viral hepatitis, fatty liver (sometimes), toxins (including medications), strenuous exercise
Alk phos tells you about the integrity of what?
Biliary tree
What are the components of total protein?
Albumin and globulin
Bilirubin is a ____________ of older blood cells
Degradation product
Bilirubin buildup can be toxic to which organ?
Brain
What are old red blood cells a source of?
Hemeproteins
What cell breaks down heme to bilirubin?
Macrophages
How is unconjugated bilirubin transported via blood to liver?
It is complexed with albumin
Once bilirubin is uptaken by the liver, what is it conjugated with?
Glucaronic acid
Where is conjugated bilirubin secreted into following the liver?
Into bile then into intestine
What happens to conjugated bilirubin in the intestine? (two steps)
Bacteria remove glnucaronic acid, then bilirubin is converted to urobilinogen
What are the three pathways urobilinogen may take from intestine?
1) Some reabsorbed from gut and enters portal blood where transported to kidney –> excreted in urine as yellow “urobilin”
2) participates in enterohepatic urobilinogen cycle
3) Oxidized by intestinal bacteria to brown stercoblin
In the kidney, urobilinogen is converted to what yellow substance?
Urobilin
If there is elevation in indirect bilirubin, would there be a defect in
a) pre hepatic
b) post hepatic
pathway?
a) pre hepatic
indirect = unconjugated
If there is elevation in direct bilirubin, would there be a defect in
a) pre hepatic
b) post hepatic
pathway?
b) post hepatic
direct = conjugated
Elevations in indirect bilirubin would NOT result from which of the following?
a) Increased production of non-conjugated bilirubin
b) Impaired conjugation of bilirubin
c) Increased hepatic uptake of bilirubin
c) is wrong results from these 3: 1) increased production 2) impaired conjugation 3) impaired hepatic uptake
Would hemolysis result in
a) elevated indirect bilirubin
b) elevated direct bilirubin
a) elevated indirect
- more unconjugated bilirubin present
