Key points Flashcards
rbc lifespan?
120 days
neutrophil lifespan?
2-4 days
lymphocyte lifespan?
1 day to yrs
platelet lifespan, hence how many days prior to major surgery should antiplatelet drugs be stopped?
10 days
must stop at least 1 wk before surgery
what is the aa substitution that takes place in sickle cell disease?
glutamic acid to valine
what is the 1st recognisable cell that begins the process of granulopoiesis?
myeloblast
derivatives of the common myeloid progenitor cell?
megakaryocyte-platelet
proerythroblast-reticulocyte-erythrocyte
mast cell (from a mast cell progenitor)
myeloblast- neutrophil, basophil, eosinophil, monoblast-monocyte-macrophage
derivatives of common lymphoid progenitor cell?
B lymphocyte- plasma cell- cancer= multiple myeloma
T lymphocyte
natural killer cell= innate immune response
why is HbA1c diabetic monitoring inaccurate in a ptnt with a hameolytic anaemia?
hamolysis= shorter half life of rbc
up until 3 mnths gestation, where does haemopoiesis in the fetus take place?
yolk sac
begins in liver from 6 wks
where does hamopoiesis take place in fetus between 6 wks and 6 mnths gestatation?
liver and spleen
what would normal bone marrow cellularity be for a patient aged 30 years old?
100-30
=70% of active bone-producing cells
predominant location of bone marrow in adult?
pelvis sternum vertebrae ribs skull
why is hepatomegaly and splenomegaly seen in myeloproliferative disorders?
BM working overtime, hamopoiesis here therefore inadequate, so also occurs in liver and spleen
what can be given to ptnts receiving chemotherapy to shorten the duration of neutropenia which increases their infection risk?
recombinant granulocyte colony stimulating factor (GCSF)
how can Fe levels be regulated in the body?
only by absorption, to match losses from bleeding, sloughed mucosal epithelial cells and pregnancy.
excess Fe CANNOT be excreted by body
what can free Fe2+ produce that is dangerous to the body?
OH and lipid free radicals which can damage lipid membranes, nucleic acids and proteins
inheritence pattern of hereditary haemochromatosis- condition in which there is increased Fe absorption from the gut?
autosomal recessive
how is hereditary haemochromatosis treated?
venesection- blood is drained off
how can Fe overload be delayed in conditions requiring regular blood transfusions e.g. thalassaemia?
use Fe chelating agents e.g. desferrioxamine
why does a macrocytosis (presence of abnormally large rbc in blood) occur with vit B12/folate deficiency?
these are required for DNA synthesis
without, rbc unable to progress from G2 to mitosis, so cells continue to grow without division.
what is a megaloblast?
an abnormal form of any precursor cell to the rbc
causes of macrocytic anaemias?
vit B12/folate deficiency alcoholism liver disease hypothyroidism Myelodysplastic syndromes Marrow infiltration Antifolate drugs e.g. Phenytoin
Give 7 causes of a normocytic anaemia
Acute blood loss Renal failure BM failure Anaemia of chronic disease Hypothyroidism Haemolysis Pregnancy
