2 Red Cells Flashcards
What provides strength and flexibility to RBC?
membrane and cytoskeleton
Are RBCs biconcave?
yes- deformability to go through splenic sinusoids
Laboratory measurements of RBC? men or women have more?
hemoglobin, hematocrit, count, cell size
Men (not diff in cell size though)
What is a network of structural proteins sitting below the plasma membrane of RBCs?
cytoskeleton
What is the predominant RBC cytoskeletal protein?
spectrin- 2 polypeptide chains which form heterodimers (HEADS ASSOCIATE TO EACH OTHER AND TAILS ATTACH TO PROTEIN 4.1 AND GLYCOPHORIN C)
What protein anchors cytoskeleton to lipid membrane?
Ankyrin through Band 3
What other items does tail of spectrin attach to?
protein 4.1 and glycophorin c
Which protein functions in anion transport (bicarb for chloride?
Band 3
What does mutations in ankyrin lead to?
loss of spectrin—>membrane loss, spherocyte shape and loss of normal deformability
Nutritional factors important for erythropoiesis?
Folate, B12 and Iron
Where is iron absorbed?
duodenum
What does iron bind after passing through mucosal cell?>
transferrin
What does RBC have to receive iron?
transferrin receptors—>endocytosed—>iron released
What happens with red cell senescence?
Red cells are engulfed by macrophages and the iron is extracted from hemoglobin—>plasma—> binds transferrin again
Where does most iron used for hemoglobin come from?
macrophages…only a small amount from dietary iron
What is an iron storage protein that sequesters iron in a non-toxic form but makes available for re-utilization?
Ferritin
Iron in excess of tissue needs is stored where?
liver
What contains 80% of body’s iron?
Red Cells
What measurements signal low iron?
serum iron low
transferrin high
ferritin low
(remember transferrin is measured as its total binding capacity. low iron means mor transferrin available)
What is needed to convert deoxyuridine to thymidine?
Folate
What vitamin is necessary for folate regeneration?
B12
Lack of folate or B12 leads to?
impaired DNA synthesis and megaloblastic anemia
Most abundant intracellular protein?
hemoglobin
3 components of hemoglobin?
globin, protoporphyrin, and iron
How many chains in hemoglobin?
4 globin chains, 2 alpha and 2 beta
basic steps of hemoglobin production?
iron+porphyrin =heme
heme +globin= hemoglobin
type of hemoglobin? 2 alphas and 2 betas?
Hemoglobin A
type of hemoglobin? 2 alphas and 2 deltas
Hemoglobin A2
type of hemoglobin? 2 alphas and 2 gammas
hemoglobin f - fetal hemoglobin is major hemoglobin during later stages of fetal development and at birth
What does high pH, low DPG and low temp lead to for O2 dissociation curve?
Increased affinity (less dissociation) left shift
T or F- RBCs don’t have a nucleus, but do have mitochondria?
False–they have neither
How does a RBC generate energy? major pathway?
glycolysis, Embden Meyerhof pathway
1 molecule of glucose lead to how many ATP in RBCs?
2 and an NADH
Deficiencies in Embden Meyerhof pathway lead to what?
hemolytic anemia
How does body limit oxidative damage?
hexose monophosphate shunt—-> produces glutathione which detoxifies H2O2
Patients deficient with G6PD?
decrease glutathione—>oxidative damage—> hemolytic anemia
What pathway leads to 2,3 BPG?
Luebering-Rappaport Pathway
What pathway maintains iron in the ferrous state?
Methemoglobin reductase pathway
Heme is broken down by proteolytic enzymes into what subsets?
iron, amino acids, porphyrin
What becomes of porphyrin?
bilirubin—>conjugated in liver and excreted
What are RBC blood groups made of?
glycosphingolipids, glycophorins, lipoproteins
T or F– c terminal sugar determines the RBC antigen?
F- n terminal
which blood type has N-acetylgalactosamine as an N terminal sugar?
Blood Type A
Which blood type has n terminal d-galactose?
Blood Type B
Which blood type has no antibodies against blood antigens?
AB
Blood D antigen positive is also called?
Rh+ and Rh- for D antigen negative
Rh negative individuals only develop anti Rh antibodies after exposure (pregnancy or blood transfusion) otherwise there are no natural occurring Rh antibodies.
What type of antibodies are for the ABO blood group?
IgM
What type of antibodies are for the Rh blood group?
IgG
T-F Surface antigens A and B are found on many cells?
True
T-F surface antigens D (Rh), Cc and E are found on many cells?
False just erythrocytes
Does Rh or ABO blood group antigens have natural occurring antibodies?
ABO
