Clin Path- Hemostasis.txt
Card Set Information
Clin Path- Hemostasis.txt
3 major components of hemostasis:
blood vessel wall, platelets, coagulation factors
How does the endothelium antagonize the formation of blood clots under normal conditions? (3)
negative surface charge, expression of endogenous anticoagulants, and production of vasodilators
After vascular injury, there is brief _______ to decrease blood flow.
Injury to the endothelium exposes the ______________, which results in ...
subenothelial extracellular matrix; platelet adhesion and activation, the primary hemostatic plug
Once the primary hemostatic plug forms, the membrane-bound protein __________ is exposed and initiates a cascade of protein coagulation factors that eventually form thrombin.
Thrombin converts __________ to __________ to form the _________.
fibrinogen; fibrin; secondary hemostatic plug
_____________________ begins almost simultaneously with clot formation.
dissolution of the clot
Overactivity of coagulation results in __________; under activity results in ___________.
thrombosis; uncontrolled hemorrhage
Nitric oxide and prostacyclin provide ___________ properties to the endothelium by inhibiting __________________.
antithrombic; adhesion of platelets
ADPase provides __________ properties to the endothelium by degrading ________, which is a _____________.
antithrombic; ADP; stimulant of platelet aggregation
Thrombomodulin provides ___________ properties to the endothelium by converting _______ from _______ to __________, activating protein C.
antithrombin; thrombin; procoagulant; anticoagulant
Proteins C and S provide _______ properties to the endothelium by degrading __________.
antithrombic; coagulation factors
Tissue plasminogen activator (tPA) promotes _________ of _________.
von Willebrand factor (vWF) is produced in _____________ and is needed for _________ to bind to ________.
endothelial cells; platelets; collagen
Tissue factor provides ____________ properties to endothelial cells by activating _____________.
prothrombic; coagulation factor cascade
Endothelial cells produce _____________ which inhibits the lysis of fibrin.
plasminogen activator inhibitors
Production of platelets depends on growth factors such as...(4)
SCF, IL-3, GM-SCF, thrombopoietin
Thrombopoietin is produced by _____________and stimulates _________ and __________;
hepatocytes; megakaryocytopoiesis; platelet production
Granules of platelets that contain Ca2+, ADP, and serotonin.
Granules in platelets that contain fibrinogen, fibronectin, vWF, thromboglobulin, growth factors, adhesion molecules, and coagulation factors.
The surface of platelets has an ___________ for secretion of granules.
open canalicular system
The platelet surface receptor glycoprotein Ib/IX/V binds ________, which bridges collagen.
The platelet surface receptor glycoprotein VI binds _______.
The platelet surface receptor glycoprotein IIb/IIIa binds ______, ______, and _______.
fibrinogen, vWF, and fibronectin
Platelet adhesion is mediated by GPIb/IX/V binding to _________ in vessels with high shear stress.
During platelet shape change, expression of a phospholipid complex on the platelet surface creates a site for _________ and _________ binding, facilitating the ______________.
calcium; coagulation factor; coagulation cascade
When platelets secrete their granules, dense bodies release _________, which is required for __________; alpha granules release __________, which promotes local _____________.
calcium; coagulation cascade; coagulation factors; clot formation
________ and _________ from activated platelets stimulate platelet aggregation.
During platelet aggregation, GPIIBIIIa binds ___________ to form bridges between platelets.
Potent vasodilator produced by intact endothelial cells that inhibits platelet aggregation.
___________ is important for platelet aggregation because it link activated platelets together to form large platelet aggregates via the ____________.
fibrinogen; GPIIbIIIa receptor
Platelets release pro-inflammatory mediators, causing ___________ to adhere to platelets and the inflammatory response that occurs with ___________.
NSAIDs inhibit _________.
Each reaction in the coagulation cascade consists of... (4)
proenzyme(substrate), activated coagulation factor (enzyme), a cofactor (reaction accelerator), and calcium ions on a phospholipid surface
The extrinsic pathway is activated by __________.
Tissue Factor (TF)
Tissue factor is expressed on _____________, and therefore is exposed at __________.
subendothelial cells; sites of tissue injury
In the extrinsic pathway, TF complexes with _______, and this complex activates ________ of the common pathway and _______ of the intrinsic pathway.
Factor VIIa; factor X; factor IX
The intrinsic pathway is activated by ___________, which is activated initially by...
factor XII; contact with negatively charged surfaces
________ of the intrinsic pathway activate coagulation and inflammation.
_________ is the first factor in the common pathway.
Xa of the common pathway converts ________ to _________.
prothrombin to thrombin
_________ is a critical accelerator for the common pathway.
Factor XIII is a cross-linking enzyme in the common pathway that _____________.
The coagulation cascade culminates in the ________________ from __________.
formation of thrombin; prothrombin
Clotting factors are produced in the ___________ as ____________.
liver; inactive pro-enzymes
How is the hemostatic process restricted to areas where it is needed only? (2)
restricting the process to phospholipid surfaces, cellular removal of activated coagulation factors
Vitamin K dependent proteins that inactivate accelerators Va and VIIIa.
Proteins C and S
During initiation of hemostasis, binding of VIIa and TF on cell surfaces generates small amounts of ________ and thrombin is formed, but cofactors are not present so...
factors IXa and Xa;a fibrin clot does not form yet
During amplification of hemostasis,_____________ allows platelets and VIII:vFW to enter subendothelial space.
loss of endothelium
Once platelets and factors enter subendothelial space during amplification, thrombin formed during initiation... (3)
activates V to Va, separates VIII from vFW, activates XI to XIa
During propagation of hemostasis, __________________, providing a surface that facilitates the coagulation cascade.
phospholipid is exposed
Tissue-type plasminogen activator is synthesized by ___________.
________ breaks down fibrinogen and fibrin.
Plasminogen activator inhibitors inhibit ________ binding to _________ to block fibrinolysis.
tissue-type plasminogen activator; fibrin
Breakdown products of fibrinogen and fibrin that result from the breakdown of fibrinogen and fibrin by plasmin.
fibrin(ogen) degradation products (FDPs)
Breakdown products of cross-linked fibrin during fibrinolysis.
_________ will artificially decrease platelet counts.
Idiopathic macrothrombocytopenia occurs in cavalier kind Charles spaniels with __________ and _________.
asymptomatic thrombocytopenia; large platelets
The buccal mucosal bleeding time test evaluates... (3)
platelet numbers, platelet function, and blood vessel function
The activated clotting time test (ACT) evaluates... (2) and may be prolonged with...
intrinsic and common pathways; severe thrombocytopenia
The Partial Thromboplastin Time test (APTT) evaluates...(2) and will be prolonged if....
intrinsic and common pathways; patient's factor activity is reduced
The Prothrombin Time test (OSPT) evaluates... (2) and will be prolonged if...
extrinsic and common pathways; patient's factor activity is low
The Thrombin Time test assays the time it takes for ______ to convert ______ to ________; prolonged time suggests....(2)
thrombin; fibrinogen; fibrin; hypofibrinogenemia; afibrogenemia
The FDP agglutination test will increased with... (3)
DIC, internal hemorrhage, or decreased clearance due to liver failure
D-dimer will be increased with... (4)
DIC, thrombotic disease, internal hemorrhage, or decreased clearance
The Antithrombin III test will decrease with... (2)
consumption or protein loss by the kidneys
Thrombelastography (TEG) measures the __________ and the ____________.
kinetics of clot formation; strength and stability of the formed clot
Abnormal bleeding can usually be characterized clinically as a disorder of... (4)
primary hemostasis, secondary hemostasis, mixed hemostatic defects, or fibrinolysis
Abnormalities of primary hemostasis are characterized by...(4)
petechiae, ecchymoses, spontaneous bleeding from mucosal surfaces, and prolonged bleeding from cuts or injection sites
Thrombocytopenia can be caused by... (4)
consumption, destruction, sequestration/hypersplenism, or decreased production
Thrombocytopenia due to consumption is associated with... (3)
hemorrhage, DIC, vasculitis
Thrombocytopenia caused by destruction is often associated with ________ in dogs; in all animals, mild thrombocytopenia may be associated with _________.
immune-mediated thrombocytopenia; vaccination
Thrombocytosis can be...(3)
physiologic, reactive, or essential thrombocythemia
Relative thrombocytosis can be associated with... (7)
increased production, inflammation, hemorrhage, iron deficiency, neoplasia, metabolic disease, trauma/surgery
Essential thrombocythemia is a ___________ with marked increased in platelet numbers and sometimes...(2)
neoplastic condition; thrombosis or hemorrhage
von Willebrand disease is an inherited disease that is common in ______; it is diagnosed by...(4)
dogs; prolonged buccal mucosa bleeding time, normal or mildly prolonged APTT, normal OSPT, low levels of vWF
Abnormal blood vessels and connective tissue structure can be associated with... (5)
vasculitis, congenital disorders (hemophilia), or acquired disorders(Cushing's disease, Vitamin C deficiency, hemangiosarcoma)
Stabilization of the primary hemostatic plug via the formation of fibrin by coagulation factors.
Abnormalities in secondary hemostasis are characterized by...(4)
hematomas, bleeding into muscles and joints, delayed bleeding, recurrent bleeding at venipuncture sites
Hemophilia is an inherited defect in ___________ that affects the __________ pathway and is characterized by... (2)
secondary hemostasis; intrinsic; prolonged APTT and normal OSPT
Hemophilia can be a deficiency of which clotting factors?
factors VIII, IX, XI, XII
Factor VII deficiency affects the _________ pathway and is characterized by... (2), affecting ______.
extrinsic; prolonged OSPT, normal APTT; dogs (beagles)
Factor X deficiency affects the _________ pathway and is characterized by...(3), affecting _______.
common; prolonged APTT and OPST, normal thrombin time; dogs (spaniels) and cats
Fibrinogen (factor I) deficiency affects the ___________ pathway.
Causes of Vitamin K deficiency...
decreased production, impaired absorption, dietary deficiency (rare), anticoagulant intoxication (Vit K antagonism)
Anticoagulant intoxication (Vit K antagonism) can be caused by... (3)
rodenticides, moldy sweet clover (cows), drugs
4 laboratory signs of Vit K antagonism.
Prolonged OSPT and APTT, normal platelets, FDPs normal, respond to vitamin K treatment
5 anticoagulant affects of liver disease.
decreased production of coagulation factors, decreased production of function factors, decreased clearance of FDPs, increased plasminogen production, decreased clearance of plasminogen activators
3 procoagulant effects of liver disease.
decreased clearance by hepatocytes of active coagulation factors, decreased production of coagulation inhibitors, altered blood flow in vascular organs
Laboratory diagnosis of liver disease is characterized by... (5)
prolonged OSPT and/or APTT, increased liver enzymes and billirubin, decreased albumin, BUN, and glucose
DDIC is always...
secondary to another process
DIC is often secondary to... (4)
neoplasia, sepsis, heat stroke, widespread abnormal activation of clotting within vessels (thrombosis)
Initiation of DIC is most commonly by __________ and activation of ________ coagulation.
tissue factor; extrinsic
Amplification and dissemination of DIC involves widespread generation of ________ and consumption of ________.
thrombin; coagulation inhibitors
During the hemorrhage phase of DIC, there is ____________, which results in...
widespread thrombosis; depletion of platelets and clotting factors
DIC is potentiated by __________.
Laboratory diagnosis of DIC involves the following...(7)
prolonged APTT and OSPT, thrombocytopenia, increased FDPs, increased D-Dimers, schistocytes, decreased antithrombin III, decreased fibrinogen(prolonged thrombin time)
____________ may occur with alterations in the blood vessel wall, activation of platelets, or changes in the balance of pro-coagulant and anti-coagulant factors.
_______ is characterized by increased endogenous production of glucocorticoids.
The mechanism of hyperadrenocorticism involves increased circulating ___________, decreased __________, _________ activation, and increased __________.
pro-coagulant factors; fibrinolysis, endothelial cell; platelet numbers
Decreased antithrombin III impairs _____________, predisposing the animal to __________.
inactivation of thrombin; thrombosis
With neoplasias, _________ are activated, there is increased expression of _________, and release of ______ from tumor cells.
endothelial cells; adhesion factors; tissue factor
The most common inherited disorder in the cat is _____________.
factor XII deficiency
Acquired disorders of primary hemostasis in cats include __________ with ___________.
vasculitis; feline infectious peritoitis (FIP)
________ is a common disorder that circulatory component in horses.
In horses, activation of coagulation normally occurs in ______________.
Acute inflammatory responses
In cattle, sweet clover toxicosis is caused by moldy sweet clover hay, which is a _____________.
vitamin K antagonist
With the APTT test, you mix ________ with... (3)
Citrated plasma; XII contact activator, phospholipid, and calcium
With the OPST test, you mix ________ with... (3)
Citrated plasma; thromboplastin (tissue factor), phospholipid, and calcium