Red cell production and turnover Flashcards
at what age do you stop producing rbcs in the femur and tibia?
20 years
how many RBCs are produced per second?
2 million
what is a proerythroblast?
day 1: the first erythrocyte precursor produced directly from multi-potential myeloid stem cells under the influence of erythropoietin
what is a basophillic erythroblast?
Day 2: smaller than the pro erythroblast with a smaller nucleus but a more basophillic cytoplasm due to increased numbers of ribosomes in cytoplasm. these ribosomes are involved in the production of haemoglobin
what is a polychromatophilic erythroblast?
Day 3: last precursor cell capable of mitosis and is smaller than the basophillic erythroblast
what is a normoblast?
day 4: is incapable of cell division and is only slightly larger than a mature erythrocyte but it does contain a small dense nucleus
what is a recticuloctye?
Days 5-7: contains some ribosomes and retains a slight basophillic stain. The clustering of the ribosomes forms a recticular network giving its name
what is an erythrocyte?
the final product of erythropoiesis and is released from the bone marrow into circulation
what % of albumin is in the plasma composition and what’s its role?
56%
Controls the osmotic pressure of plasma, transport fatty acid, thyroid hormones, moves bilirubin
what % of globulins make up plasma proteins and what’s the role?
36%
antibodies - attack foreign proteins and pathogens
transport globulin - bind small ions, hormones and compounds and transport them
what % of fibrinogen makes up plasma proteins and what’s is the role?
7%
form insoluble stands of fibrin leading to blood clot
how long do RBCs live?
120 days
after 120 days what happens to RBCs
10% rupture (haemolyses) and 90% are engulfed by phagocytes
what happens to urine if large numbers of RBC rupture?
urine may turn red/brown due to presence of haemoglobin
what is haematuria?
the presence of intact RBC in urine
what is the structure of erythrocytes?
membrane has a lipid bilayer and an outer glycoprotein coat
the inner protein molecules form a filamentous cytoskeleton
(spectrin, actin, ankyrin)
No sub-cellular particles
what is glucose uptake via?
GLUT 1 transporter
what does decreased oxygen supply stimulate?
secretion of erythropoietin from cells in the kidney, EPO stimulates bone marrow to produce RBCs, EPO accelerates nearly all stages of RBC formation
what are factors affecting RBC production?
Iron - essential for RBC formation because of its role in haemoglobin structure formation
Vitamin B12 and folic acid - essential for final maturation of RBCs
Vitamin C - important in reducing the ferric form of iron to ferrous to facilitate its absorption and transport
what are the antibodies and antigens present in group A
antibodies - anti-B
antigens - A antigen
what are the antibodies and antigens present in group B
antibodies - Anti-A
antigens - B antigen
what are the antibodies and antigens present in blood group AB?
antibodies - none
antigens - A and B
what are the antibodies and antigens present in group O
antibodies - anti-A and anti-B
antigens - none
what are group AB known as?
universal recipients - don’t agglutinate any of ABO bloods
