Coagulation - Final Exam Flashcards
Normal Hemostasis is a balance b/w what 3 things?
- clot generation
- thrombus formation
- counter-regulatory mechanisms that inhibit uncontrolled thrombogenesis (clot formation) or premature thrombus degradation
What are the 3 goals of hemostasis?
- limit blood loss from vascular injury
- maintain intravascular blood flow
- promote revascularization after thrombosis
Stages of Hemostasis
What is primary hemostasis?
What does it lead to?
What kind of injury is it adequate for?
- immediate platelet deposition at the endovascular injury site
- leads to initial platelet plug formation
- minor injuries
Stages of Hemostasis
What is secondary hemostasis?
- where clotting factors are activated & a stabilized clot is formed w/ crosslinked fibrin
Hemostasis
Vascular endothelial cells have ________, ________, and ________ effects that inhibit clot formation.
- antiplatelet
- anticoagulant
- profibrinolytic
Hemostasis
Vascular endothelial cells are ________ charged to repel ________.
- negatively
- platelets
Hemostasis
What platelet inhibitors do vascular endotheloal cells produce?
- Prostacyclin
- Nitric Oxide
Hemostasis
What do vascular endothelial cells excrete that degrades ADP?
What is ADP’s role in hemostasis?
- they excrete adenosine diphosphatase
- ADP is a platelet activator
Hemostasis
True or False?
Vascular endothelial cells inactivate protein C?
- what is protein C’s role in anti-clotting?
False. They increase protein C, which is an anticoagulant
Hemostasis
True or False?
Vascular Endothelial cells produce tissue factor pathway inhibitor (TFPI).
What does TFPI inhibit?
- True
- TFPI inhibits factor Xa and TF-VIIa complex
Hemostasis
Where is tissue plasminogen activator (t-PA) synthesized?
in vascular endothelial cells
Hemostasis
Where are platelets derived from?
bone-marrow megakaryocytes
Hemostasis
What do inactive platelets circulate as? What is their lifespan?
- discoid anuclear cells
- lifespan: 8-12 days
Hemostasis
In normal conditions 10% of platelets are consumed to support ________ ________.
How many platelets are formed daily?
- vascular integrity
- 1.2-1.5 x 10^11 (1 billion)
Hemostasis
What does the platelet membrane contain that increases the surface area?
- numerous receptors
- surface canalicular system (channels in the membrane that help the platelet function)
Hemostasis
What expose the extracellular matrix?
Damage to the endothelium
Hemostasis
What 3 things are found in the extracellular matrix?
- collagen
- Von Willebrand’s Factor
- other platelet adhesive glycoproteins
Hemostasis
What are the 3 phases that platets undergo after exposure to the extracellular matrix?
- Adhesion
- Activation
- Aggregation
Platelet phases
What initiates adhesion of platelets?
- exposure to extracellular matrix proteins
Platelet phases
Activation of the platelet is stimulated when the platelet interacts with ________ & ________ ________.
What does activation of the platelet cause?
- Collagen & tissue factor (TF)
- Activation causes release of granular contents of the platelets
What are the 2 types of storage granules in platelets?
- alpha granules
- dense bodies
Platelets
What contents are release from alpha granules?
- fibrinogen
- Factors V & VIII
- vWF
- Plt-derived growth factor
- & more
Platelets
What contents are released from dense bodies?
- ADP
- ATP
- Calcium
- Serotonin
- Histamine
- Epinephrine
Platelet Phases
When does platelet aggregation occur?
What does this recruit and activate?
Then ________ ________ coagulation is propagated.
- Occurs when granular contents are released
- this recruits and activates more platelets
- plasma-mediated coagulation propagated
Platelet Aggregation
What binds to fibrinogen and promotes fibrin crosslinking?
- activated glycoprotein IIb/IIIa receptors on the platelet’s surface
Hemostasis
What does each stage of the clotting cascade require assembly of?
- membrane-bound activation tenase complexes
What 4 things are each membrane-bound activation tenase-complex composed of?
- substrate (inactive precursor)
- enzyme (activated coagulation factor)
- cofactor (accelerator or catalyst)
- calcium
Clotting Factors
Factor I
Fibrinogen
Clotting Factors
Factor II
Prothrombin
Clotting Factors
Factor III
Tissue Thromboplastin
Clotting Factors
Factor IV
Calcium Ions
Clotting Factors
Factor V
Labile Factor
Clotting Factors
Factor VII
Stable Factor
Clotting Factors
Factor VIII
Antihemophilic Factor
Clotting Factor
Factor IX
- Christmas Factor
or - Plasma Thromboplastin Component (PTC)
Clotting Factors
Factor X
Stuart-Prower Factor
Clotting Factors
Factor XI
Plasma Thromboplastin Antecedent (PTA)
Clotting Factors
Factor XII
Hageman Factor
Clotting Factors
Factor XIII
Fibrin Stabilizing Factor