Haematology Flashcards
Describe erythropoiesis?
In the bone marrow, erythropoiesis takes place, through a series of differentiation steps, haematopoietic stem cells become reticulocytes. Reticulocytes remain in the bone marrow for 3 days before they are released into the circulation.
After circulating in the blood for 1 day, they transform into fully mature RBC, which circulate for around 120 days before being removed by macrophages.
how can anaemia be classified?
Microcytic (MCV <80)
Normocytic
Macrocytic (MCV > 100)
what are causes of microcytic anaemia?
iron deficiency anaemia
haemoglobinopathies - thalassemia
inflammation - chronic inflammation can cause anaemia
lead poisoning
copper deficiency
sideroblastic anaemia
what is the role of iron in the body?
enzymatic processes
DNA synthesis
oxygen transport
mitochondrial energy generation
describe how iron is absorbed into the body?
iron is typically ingested in Fe3+ form. This cannot be absorbed by the small intestine lumen, and therefore is converted at the small intestine cells to Fe2+ which can easily be absorbed.
Once absorbed, it is converted back into Fe3+, and transported around the body via transferrin.
The iron is taken to either the bone marrow, where iron is used by haemoglobin to carry oxygen. Some of the iron is also taken to the liver, where the liver can store iron as ferritin.
what is the role of transferrin?
to transport iron (ferritin) around the body.
what factors regulate iron concentration in the plasma?
hepicidin - this is produced by the liver, and typically will work to limit iron release into circulation.
what is tested for in blood iron studies?
iron studies - ferritin, transferrin, serum iron, TBIC
what does iron deficiency anaemia show on iron studies blood tests?
MCV - low
serum iron - low
ferritin - low
transferrin - elevated (this is to compensate for the low ferritin)
TBIC - high
