hemostasis Flashcards
the process of hemostasis involves what 4 things?
vessel wall,
platelets,
coagulation cascade,
fibrinolytic system
cell based theory of coagulation
posits that coagulation occurs on different cell surfaces that contain tissue factor (TF)
vessel structure of arteries and veins
tunica adventia(outer), tunica media, tunica intima
vessel structure of capillaries
single layer of endothelial
endothelial cells synthesize and secrete
procoagulants,
anitcoagulants,
fibrinolytics (vWF, tissue factor, NO, prostacyclin, thromboxane a2, ADP, tissue factor pathway inhibitor
the tunica intima (endothelial layer) forms a barrier separating fluid contents within the blood vessel from the highly ________ material that lies in the tunica media
thrombogenic
necessary cofactor for adherence of platelets to the subendothelial layer
Von Willebrand factor (vWF)
Activates the clotting cascade pathway when injury to the vessel occurs
tissue factor
endothelial cells- vasoconstriction
thromboxane A2,
Adenosine diphosphate (ADP),
Setotonin
endothelial cells- vasodilation
nitric oxide,
prostacyclin
endothelial cells- coagulation inhibitors
tissue factor pathway inhibitor
extremely thrombogenic, very active, collagen and fibronectin
tunica media-subendothelial
control of blood flow by influencing the vessel’s degree of contraction via vasodilation by: NO, Prostacyclin
tunica adventitia- third layer
Mediators of intima
vWF,
tissue factor,
prostacyclin,
nitric oxide
mediators of media layer
collagen and fibronectin
mediators of adventitia
nitric oxide and prostacyclin
procoagulant mediators
collagen, vWF, and fibronectin (coagulation factors, protein c and s, thrombomodulin)
collagen function
tensile strength
vWF function
adhesion
protein c function
degrades factors v and VII
protein s function
cofactor for protein c
fibronectin function
mediates cell adhesion
thrombomodulin function
regulates anticoagulant pathway
anticoagulant mediators
antithrombin II and tissue pathway factor inhibitor
Antithrombin II function
degrades factors XII, XI, X, IX, II
tissue pathway factor inhibitor function
inhibits tissue factor
vasodilation mediators
nitric oxide and prostacyclin
prostacyclin function
vasodialates, inhibits aggregation (both prostacyclin and NO promote smooth-muscle relaxation)
vasoconstriction mediators
thromboxane A2, ADP, and serotonin
Fibrinolytic mediators
plasminogen, tPA, and urokinase
Plasminogen function
converts to plasmin
tPA and urokinase functions
activates plasmin
antifibrinolytic mediators
plasminogen activator inhibitor, and a-antiplasmin
plasminogen activator inhibitor function
inactivates tPA, urokinase
a-Antiplasmin function
inhibits plasmin
Essential component to the thrombogenic response,
round, disk like, circulate freely in the blood
the Platelet
Where is the platelet formed?
in the bone marrow
Daily use of plts by body
7.1x10^3 (7,100)
platelet cell characteristics
contain mitochondria, glycogen stores,
contractile proteins, calcium, enzymes
alpha granules
vWF, fibrinogen, fibronectin, platelet factor 4, platelet growth factor, (VFFPP)
Dense granules
Serotonin, ADP, ATP, Histamine, Epinephrine
Do platelet cell produce thrombin?
yes, activates coag factors and influence recruitment of platelets
Do platelets have a nucleuse, RNA, DNA?
NO
T/F: Plts are inactive unless activated as a result of tissue trauma
TRUE
IS adequate hemostasis possible in the absence of activated platelets?
NO
formation of plug involves
adhesion, activation, aggregation
adhesion involves
vWF mobilizes from endothelial cells, glycoprotein Ib receptors emerge from surface of platelet. GpIb attaches to vWF and attracts additional plts to the endothlial lining while vWF makes plts “sticky”
What causes the platelt to undergo a conformational change and become________
tissue factor “activated”
What are the little cell feet activated platelets show?
pseudopodia
When the GpIIb-IIIa receptor complex links activated platelets together to form a primary platelet plug, this is known as?
aggregation
As plts undergo this “activation” process they release _____ and _____ granules, contractile granules, thrombin, and procoagulant mediators into the blood.
alpha and dense
coagulation cofactors are known as
zymogens
cofactors are enzymes with the exception of factor __ and ___ and circulate in an inactive state until activated
V and VIII
Factor I: name, synthesized, vit k dep, action
fibrinogen,
Liver,
No vit k,
Forms a clot
Factor II: name, synthesized, vit k dep, action
Prothrombin,
Liver,
Yes vit k,
when activated, activates I,V,, VII, XIII, plts, and protein C
Factor III: name, synthesized, vit k dep, action
Tissue Factor or Thromboplastin,
Vascular wall and extravascular cell membranes, released from traumatized cells,
Cofactor of VII
Factor IV:name, synthesized, vit k dep, action
Calcium,
Diet,
Promotes clotting reactions
Factor V: name, synthesized, vit k dep, action
Proaccelerin, Liver,
No vit k,
Cofactor of X, forms a prothombinase complex
Factor VII: name, synthesized, vit k dep, action
Proconvertin,
Liver,
YEs vit k,
Activates IX and X
Factor XIII: name, synthesized, vit k dep, action
Antihemophiliac,
Liver,
No vit k,
Cofactor to IX
