Card Set Information
RBC life cycle
Characteristics of RBCs:
Hemoglobin synthesis requires 3 basic components:
and Folic Acid
Functions of RBCs:
Transports oxygen from lungs to tissues.
from tissues to the lungs.
Glycoprotein hormone (growth factor) that stimulates erythropoiesis.
Where does erythropoietin happen?
85% in kidneys, 15% in liver
Erythropoietin synthesis is stimulated by and located on chromosome:
Decreased blood oxygen (hypoxia) is detected by special kidney cells, which:
Stimulates them to produce erythropoietin
Erythropoietin is secreted into the:
blood and travels to the bone marrow
Can RBCs counts get too high?
Yes, blood becomes so thick, heart can not pump leads to clot/blood vessel.
Increased RBC concentration
Increased numbers of RBCs (High erythropoietin, smokers, chronic lung disease, abnormal hemoglobin molecules, renal tumors, genetic disorders)
Decreased plasma volume (Not related to high erythropoietin, RBC numbers are not increased, Dehydration from burns, diarrhea, decreased fluid intake or exposure to excessive heat)
Developement and maturation of RBCs:
: Fine chromatin, 0-2 nucleoli, basophilic cytoplasma, receives iron from hemoglobin.
Prorubricyte (Basophilic normoblast)
:Thicker chromatin, no nucleoli
Rubricyte (Polychromatic normoblast)
: Coarse chromatin, "muddy grey" cytoplasm 1st visible hemoglobin
Metarubricyte (Orthochromatic normoblast)
: Pyknotic nucleus (dark solid), pinkish cytoplasm
: Anuclear RBC with bluish tint
Erythrocyte (Mature RBC)
: Anuclear, pink-red cytoplasm
Delayed nuclear maturation but normal cytoplasm maturation.
Immature nucleus and mature cytoplasm.
The nucleus and cytoplasm are asynchronous
Common cause of megaloblastic maturation is B
RBC after nucleus is lost.
Briefly retains RNA, causing bluish discolorization (Wright stain)
When is the RNA lost in a reticulocyte?
1-2 days after release
Under normal conditions in retic:
Bone marrow retics replace old RBCs removed from circulation.
# marrow RBCs=# Blood retics=#RBCs removed from blood
Reticulocytes released earlier than normal to meet increased demand.
Immature, larger than normal and have a
darker bluish color.
Common test to measure bone marrow erythropoiesis.
RNA will stain a smooth light blue color with the Wright Stain.
RNA is precipitated and stains as bluish granules (speckled appearance) with Methylene Blue stain.
Retics are expressed as a _____.
% of total RBCs
Retic counts are performed in 2 ways:
Microscopic exam of Methylene blue stained blood smear.
Automated analysis of Methylene blue stained whole blood
What is the corrected retic formula?
(patient HCT/Normal HCT) retic %
Uncorrected Retic formula:
#retics/#RBCs x 100
(RPI) Reticulocyte Production Index:
Corrected Retic count/Maturation time
RPI is done to correct:
For apparent increase in erythropoiesis
Hemoglobin is a large, coiled, conjugated protein molecule that is composed of:
4 polypeptide chains composed of amino acids.
4 heme groups
4 iron molecules, 1 in each heme group
2 alpha-2 beta chains
Molecule found inside the RBCs
2-3 DPG is high the oxygen will leave the RBC cell to the other cells (good).
If low it will soak up the oxygen.
Increased 2-3 DPG _________ affinity:
Increased temp _________ affinity.
Increase pH __________ affinity
Shift to Left
Shift to right
Fetal hemoglobin has _______ O
affinity than HGB A. Pulls O
across placenta from mother to fetus.
2 Alpha-2 gamma
Synthesis begins at 5 weeks gestation and associated with hepatic hematopoiesis
Carbon Dioxide Transport. Hemoglobin is also needed to transport carbon dioxide from the tissues back to _______ for removal.
Carbon dioxide transported
3 different ways
_____ Indirect RBC pathway (conversion of CO
____ Direct pathway
____ Dissolved in plasma
75%, 20%, 5%
Disorder of heme synthesis
Causes of porphyrias:
Genetic deficiencies of enzymes required for heme synthesis.
Acquired deficiencies from substances that damage heme synthesis.
Porphyrias are diagnosed:
From detection of heme pre-cursors molecules in the urine
Ferric iron is transported to the immature marrow RBCs by the protein ______.
Transferrin delivers ____ to the immature RBC membrane and then returns to the plasma.
Excess iron is stored as ________ in tissues and plasma.
Excess iron may accumulate in immature RBCs
2 alpha-2 delta
2 alpha-2 beta (
2 alpha-2 beta (
Hemoglobin affinity for CO >200 x that of oxygen.
Hgb binds CO and releases it very slowly.
Can carboxyhemoglobin transport oxygen?
Hemoglobin combined with sulfur compounds.
Hemoglobin shape altered, preventing oxygen transport.
May denature and precipitate to form
Common causes of sulfhemoglobin:
Hemoglobin with ferric iron.
Caused by genetic defects/oxidizing drugs
Analytical technique that separates substances according to their different migration rates (movement) in an electric field.
Commonly used to confirm a hemoglobinopathy diagnosis.
What are the 2 most common hemoglobin electrophoresis technique:
Cellulose acetate has a pH of:
Citrate agar has a pH of:
Fetal Hemoglobin stain or Hemoglobin F stain is also known as:
useful to ID fetal blood in the maternal circulation
Main energy source/ATP from glucose
Hexose Monophosphate Shunt:
Prevents oxidative denaturation of hemoglobin and Heinz Body formation
Methehemoglobin reducatase pathway:
prevent oxidation of hemoglobin iron to Fe
Regulates 2-3 DPG concentration in the RBCs
What is the average lifespan of RBCs?
As RBCs age what happens:
Membrane become less flexible
Enzyme activity decreases.
Cell loses membrane-RBC hemoglobin increases
Cup of grace Coup de grace:
As RBC's become stiff, they get stuck passing through the spleen.
Phagocytized and removed from the circulation by the spleen.
RBCs are destroyed.
The components of the RBCs must be re-utilized or excreted.
Extravascular catabolism (Intracelluar):
Happens in spleen. Inside the RE cells of spleen.
Heme is broken apart and concerted into bilirubin and excreted into the GI tract by the liver.
Intravascular catabolism (in the circulating blood):
RBCs hemolyze, releasing the cytoplasm into the plasma.
Plasma protein binds polypeptide chains, preventing their loss in the urine.
Haptoglobin-protein complexes removed by the liver.
Additional unbound plasma hemoglobin oxidized to
Mean Corpuscular volume
How big, average
Mean Corpuscular Hemoglobin
How much hemoglobin in cell.
Mean Corpuscular Hemoglobin Concentration
Concentration of hemoglobin
Formula for MCV:
Formula for MCH:
HGB/ RBC (10)
Formula for MCHC: