Haematopoiesis and Anaemia Flashcards
Identify the lifespan of the following:
- RBCs
- Neutrophil
- Lymphocytes
- Platelets
Erythrocytes - 120 days life
Neutrophil - 9 -10 hours in the blood, few days in the tissues
Lymphocytes - some long lived (memory cells) some short-lived (plasma cells)
Platelets - 4 - 5 days in the blood
How do drugs and chemotherapies affected different kinds of blood cells ?
Will see an impact on short-lived cells first (i.e. neutrophils will often be depleted first, as neutropenia; which can make vulnerable to bacterial infections)
How do blood cells migrate from bone marrow to blood ?
Escape through gaps (apertrures) in walls, into sinusoids ( small blood vessels)
What is the function of a megakaryocyte ?
Fragmenting to produce platelets
Identify the types of stem cells in the bone marrow.
Haematopoietic (Those that supply RBCs and immune system cells)
Stromal (make up connective tissue)
Identify the types of bone marrow.
Red marrow (myeloid) contributes blood cells Yellow marrow due to fat cells
Describe the balance between red and yellow marrow in humans.
At birth most marrow is red, yellow
increases with age.
In severe anaemia yellow marrow can
convert back to red marrow
What is the mass of bone marrow in an adult ?
2.5 Kg
Where is red marrow located ?
Red marrow mostly located in flat bones
ie hip, sternum,ribs, verterbrae, shoulder blades
What is a common site of bone marrow harvest ?
Sacro-iliac crest
What are the main sources of haematopoietic cells in the foetus and adult ?
FOETUS: liver and spleen is the main source of haematopoietic cells
POSTNATAL: initially long bones, then flat bones as turn adult
How may treatment on a pregnant woman affect foetal RBC and stem cell production ?
If said treatment affects the liver (since liver and spleen is the main source of haematopoietic cells in foetus)
Describe the process of erythropoiesis.
Large erythroblastoid cell —> Multiple (6-7) divisons and maturation as move towards smaller almost functional cells –> Increase in Hb and expel nucleus –> Classic RBC for release into bloodstream
Defined erythropoietin and its function.
-Glycoprotein hormone produced
by fibroblasts in kidney – regulates rbc release (by co-operating with growth factors such as Burst Forming Unit- Erythroid (BFU-E) and Colony Forming Unit –erythroid (CFU-E) in development of precursors of red cells)
-Under hypoxia, epo released to stimulate Rbc production
Describe the effect of high altitude, hypertransfusion, chronic renal failure, some kidney tumours, and anaemia on erythopoiesis.
High altitude = Low O2 concentration = Epo increased = Red cell mass increase (and increase in hematocrit)
Hypertransfusion = Epo decreased = switch off red cell production
Chronic renal failure = O2 sensor damaged = Epo loss = Anaemia (and cannot respond by producing Epo, so severe anaemia in chronic renal failure)
Kidney tumours = Epo excess = Polycythaemia (too many RBCs, higher risk of clots and strokes)
Anaemia = more Epo produced to compensate for low Hb (as Hb is lost, EPO is increased to compensate.)
