Lecture37: Platelets And Thrombopoiesis Flashcards
What is the origin of platelets?
Megakaryotes in the bone marrow
How long do platelets live?
10 days
What are GPs (Polymorphic glycoprotein molecules) involved in?
Platelet adhesion
What is the peripheral clear region in the cytosol called?
Hyalomere
What is the central darker region in the cytosol called?
Granulomere
What is the Hyalomere cytoskeleton formation?
15 microtubules arranged in parallel
Does the Hyalomere have Actin and Myosin?
Yes
What is the Actin and Myosin Function in the Hyalomere?
Platelet movement and retraction
What does the OCS (open canalicular system) connect to in the Hyalomere?
Invaginations of the plasmalemma
What does the OCS do?
Entry of external elements and storage of GPs, as well as filopodia formation
What does the DTS do?
Calcium release
What are the granules that the Granulomere displays?
Alpha, delta, and Lambda
What does the Granulomere do?
Has enzymes that produces ATP and consume oxygen
What is the Alpha Granule in charge of?????
Coagulation, anticoagulation
What is the delta granules in charge of?
Serotonin and ATP/ADP
What do the GPs do in the First step of platelet adhesion?
They bind to collagen and vWF
What happens in stage 2 (platelet shape changes) ?
The extra cellular calcium influxes and so intracellular calcium releases
What binds the GP2 receptors in aggregation?
Fibrinogen
What happens to form the secondary hemostatic plug?
Fibrinogen broken down by thrombin to form fibrin, and thus stabilize
What are the Antiplatelet agents?
TXA2 inhibitors
Which 2 factors does antithrombin 2 inhibit?
2a and 5a
What does heparin do?
It’s an anticoagulant by enhancing antithrombin 3 activity
What does protein C inhibit?
Factors 5 and 8
What does prostacyclin inhibit?
It’s a vasodilator, thus it inhibits platelet activation
Does NO inhibit platelet adhesion?
Yes
What maintains an anti thrombotic surface??
TFPI (Tissue-Factor Pathway Inhibitor)
What does Vitamin K do?
It’s deficiency causes bleeding
