Blood Cells and Disorders II Flashcards
What does thrombopoietin cause haemopoeitic stem cells to differentiate into?
Megakaryoblasts to produce megakarocytes
What are platelets?
Small anucleate cells for haemeostatis with 5-9 day lifespan
What 3 steps occur following an injury in haemostatis?
Vascular spasm (arteries/arterioles constrict to reduce blood flow) , Platelet plug formation, Blood clotting
what are the steps platelet plug formation?
adhesion, outside-in signalling - integrin activation, secretion, aggregation, thrombin production
What ECM proteins does platelet plug formation require?
vWF, fibrinogen and collagen
What 2 platelet disorders are there?
Bernard-soulier : abnormality in gene for glycoprotein Ib/V/XI
Glanzmann thrombasthenia: abnormality in gene for glycoprotein IIb/IIIa
What are symptoms for platelet disorders?
Easy bruising, nose bleeds, bleeding from gums, prolonged heavy menses, abnormal bleeding after surgery, rarely (vomit blood, pass blood)
What can storage pool deficiencies be caused by?
Lack of granules, or failure of platelets to empty the granules
What is delta storage pool deficiency?
A lack of dense granules or can be of other inherited conditions (hermansky pudlak and chediak-higashi syndrome)
What is Grey platelet syndrome?
Rare platelet disorder by lack of alpha granules and chemicals stored inside them so proteins cant stick to blood vessel wall or clump or repair injured site
What is extrinsic blood coagulation?
fewer and rapid, initiated by TF leaking into blood from cells outside the blood stream
FVII activated by thrombin and FXa, FVIIa activates FX
What is intrinsic blood coagulation?
More complex and slower - outside tissue damage is not needed e.g endothelial cell damage
FXII activates FXI releases bradykinin (vasodilator) from HMWK, activate FIX (serine protease) hydrolyses FX - leading to common pathway
What is common pathway?
FXa cleaves prothrombin on surface, FV activated by thrombin, Fibrinogen to fibrin by thrombin, thrombin activates FXIII crosslinks fibrin clot
What is clot retraction??
Tightening of fibrin clot
What is fibrinolysis?
dissolves small inappropiate clots and dissolved clots at sites of repair, inactive plasminogen incorporated into clot activated to plasmin by body tissue substances like thrombin, plasmin digests fibrin threads and inactivates fibrinogen
What is haemophilia A in terms of genetic disease?
X linked leading to FVIII deficiency