Coagulation Flashcards
Exam 4
Normal hemostasis is a balance btw ______, ________, and _______ that inhibit uncontrolled thrombogenesis
clot generation, thrombus formation, and regulatory mechanisms
What are the 3 goals of hemostasis?
- to limit blood loss from vascular injury
- maintain intravascular blood flow
- promote revascularization after thrombosis
What are the 2 stages of hemostasis?
Primary:Immediateplatelet deposition at the endovascular injury site (initial platelet plug formation, minor injuries)
Secondary: clotting factors activated, stabilized clot formed, and secured with crosslinked fibrin
Vascular endothelial cells have ________, ________, and ________ effects to inhibit clot formation
antiplatelet, anticoagulant, fibrolytic
Anti-clotting mechanisms of the endothelial cells are _______ charged to repel ________
negatively, platelets
Anti-clotting mechanisms of the endothelial cells produce platelet inhibitors such as ________ and ________
prostacyclin and nitric oxide
Anti-clotting mechanisms of the endothelial cells excrete __________, which degrades adenosine diphosphate (ADP), a _______ activator
adenosine diphosphatase
platelet
Anti-clotting mechanisms of the endothelial cells increase ________, an anticoagulant, and synthesize ______
protein C, tissue plasminogen activator (t-PA)
Anti-clotting mechanisms of the endothelial cells produce Tissue Factor Pathway Inhibitor (TFPI), which inhibits factor___ & ______
Xa and TF-VIIa complex
Platelets are derived from
bone-marrow megakaryocytes
Inactive platelets circulate as disc-shaped _______ cells with a lifespan of _______
anuclear, 8-12 days
Approx __% of platelets are consumed to support vascular integrity with ________ new platelets formed daily
10%, 120-150 billion
The platelet membrane contains numerous receptors and a surface ________system, which increases membrane __________
canalicular, surface area
Damage to endothelium exposes the underlying extracellular matrix (ECM), which contains what 3 things?
collagen, von Willebrands factor, and other glycoproteins
Upon exposure to contents in the ECM, platelets undergo 3 phases of alteration:
- 1st: adhesion
- 2nd: activation
- 3rd: aggregation
______: occurs upon exposure to ECM proteins
Adhesion
_________:stimulated when platelet interacts w/collagen & tissue factor (TF), causing the release of granular contents
Activation
Which 2 types of storage granules do platelets contain?
alpha granules and dense bodies
________: occurs when the granular contents are released, which activate additional platelets, propagating plasma-mediated coagulation
Aggregation
Alpha granules contain
fibrinogen, factors V & VIII, vWF, Plt-derived growth factor
Dense bodies contain
ADP, ATP, calcium, serotonin, histamine, epinephrine
Each stage of the clotting cascade requires the assembly of membrane-bound activated tenase-complexes composed of
1) a substrate (inactive precursor)
2) an enzyme (activated coagulation factor)
3) a cofactor (accelerator or catalyst)
4) calcium
Factor 1 aka ______
fibrinogen
Factor 2 aka ______
prothrombin