Lecture 3 1/23/24 Flashcards
What is the CBC rule of 3?
-RBC count x 3 = Hgb estimate
-Hgb estimate x 3 = HT/PCV estimate
How many molecules of oxygen is bound to each hemoglobin molecule?
4
Which protein makes up the majority of the dry content of blood?
hemoglobin (95%)
Which peptide chains form hemoglobin?
-2 alpha chains
-2 non-alpha chains
How do embryonic, fetal, and adult hemoglobin differ, in terms of peptide chains?
-adult Hgb has 2 beta chains
-fetal Hgb has 2 gamma chains in most species
-embryonic Hgb has 2 epsilon chains
Why do embryonic and fetal Hgb have gamma/epsilon chains instead of beta chains?
-epsilon and gamma chains have a higher affinity for O2 than beta chains
-helps get O2 to the embryo/fetus
Which species make use of the 2,3-DPG protein in the fetus instead of hemoglobin gamma chains?
-dogs
-pigs
-horses
What are the characteristics of heme?
-ring-shaped metallic compound
-contains one iron atom each
-can bind to one O2 molecule each
Why is it important that the iron atom in heme is an Fe2+ atom and not an Fe3+ atom?
Fe3+ is unable to bind O2
Where is hemoglobin synthesized?
mitochondria and cytoplasm
How does oxidative stress impact cells?
removes e- and leads to cell damage
What are the characteristics of the pentose shunt?
-NADPH is produced
-NADPH is used as a reducing agent by GSH
-e- are transferred to hemoglobin
What are the characteristics of the methemoglobin reductase pathway?
-protects iron and keeps it in an Fe2+ state
-methemoglobin contains Fe3+ and cannot bind O2
What are the characteristics of the DPG shunt?
-produces 2,3-DPG when oxygen needs to be released more easily
-present in all species
-low concentration in fetal dogs/pigs/horses to allow fetal hemoglobin to bind O2
Why do RBCs produce reducing agents?
to protect hemoglobin, iron, and cell membranes from oxidative species
How do RBCs obtain energy?
converting glucose into 4 ATP through aerobic glycolysis
What are Heinz bodies?
precipitations of denatured hemoglobin
What conditions cause the oxygen-hemoglobin curve to move to the left?
-low H+/high pH
-low temp
-low CO2
-low DPG
What conditions cause the oxygen-hemoglobin curve to move to the right?
-high H+/low pH
-high temp
-high CO2
-high DPG
How does moving the oxygen-hemoglobin curve impact oxygen release from hemoglobin?
-moved left: less easily released
-moved right: more easily released
What is positive cooperativity?
-the binding of O2 to one hemoglobin unit, it makes it easier for O2 to bind to a second hemoglobin unit, and so forth
-also works in reverse with release of O2 from hemoglobin units (first O2 removed is the hardest, easier with each successive molecule)
What determines different blood groups/types?
the absence or presence of erythrocyte surface antigens
What is an alloantigen?
antigen present in some members of the same species but not common to all members
What are alloantibodies?
antibodies produced against an alloantigen when the individual does not naturally express the antigen
