Haematopoiesis and Anaemia Flashcards
what is the lifespan of erythrocytes?
120 days half-life
what is the lifespan of a neutrophil
- 9-10 hours in blood
- few days in tissues
what is lifespan of lymphocytes?
- memory cells: long-lived
- plasma cells: short-lived
what is lifespan of platelets?
4-5 days in blood
what are the two types of stem cells?
- haematopoietic
- stromal
what are the two types of marrow?
- red (myeloid)
- yellow
what does red marrow contribute?
blood cells
what does yellow marrow contribute?
fat cells
where is red marrow located?
flat bones:
- hip
- sternum
- ribs
- vertebrae
- shoulder blades
what can happen to yellow marrow in severe anaemia?
convert back to red marrow
in foetus, what is the main source of haematopoietic cells?
liver, then long bones, then flat bones
what is erythropoietin?
- glycoprotein hormone produced by fibroblasts in kidney (regulates rbc release)
- co-operates with growth factors such as BFU-E and CFU-E in development of precursors of red cells
under hypoxio, what is released?
EPO to stimulate rbc production
what is BFU-E?
burst forming unit-erythroid
what is CFU-E?
colony forming unit-erythroid
what causes EPO and red cell mass to increase?
- high altitude
- low oxygen conc.
what causes EPO to decrease and red cell production to switch off?
hypertransfusions
what happens to EPO conc. with chronic renal failure?
O2 sensor damaged, EPO loss
what happens to EPO with some kidney tumours?
EPO excess
what does EPO loss cause?
anaemia
what does EPO excess cause?
polycythaemia (too many RBCs)
