Intro to haem system Flashcards
Where does haemotopoiesis occur in the embryo?
yolk sac then liver then marrow (spleen as well from 3-7months)
Where does haematopoeisis occur in the adult?
bone marrow of skull; ribs; sternum; pelvis and prox ends of femur
How are platelets formed?
budding on the periphery of megakaryocytes
What RBCs are found in the plasma?
reticulocytes and mature RBCs
What differentiates between reticulocytes and mature RBCs?
reticulocytes still have RNA (blue) and are larger
what is the structure of eosinophils?
bi-lobed with bright orange-red granules
What is the appearance of basophils?
large depp purple granules obscuring nucleus
How long do monocytes circulate in the blood?
a week before entering tissues to become macrophages
How do mature lymphocytes appear?
small with condensed nucleus and rim of cytoplasm
What are activated lymphocytes often called?
atypical
How do atypical lymphocytes appear?
large with plentiful blue cytoplasm extending round neighbouring red cells, open chromatin in nucleus
What does the presence of atypical lymphocytes suggest?
intercurrent viral infection
where is the most common site for bone marrow aspiration and bippsy?
psoterior iliac crests
What is a bone marrow biopsy known as?
trephine biopsy
What is the allosteric effect in Hb?
as one O2 binds it alters the bidning affinity for the next O2
What is the difference in affinity between HbA; HbF and myoglobin?
myoglobin has highest affinity for O2 followed by fetal then adult
What is the average O2 venous partial pressure?
5.3
What is average O2 arterial partial pressure?
13.3
What results in a shift in the oxyhaemoglobin curve to the right?
decreased pH; increased DPG; temp; CO2 and H+
Why does the RBC rely on pumps so much?
high osmotic pressure due to so much protein (Hb)
What is Hb oxidised with Fe3+ called?
metHb
What is the problem with metHb?
can’t carry oxygen
Why is the RBC membrane protein rich?
essential for membrane flexibitiy to get through capillaries
What is the rapapoport-Lubering shunt?
generates 2,3 DPG that releases more oxygen
