Anemias and blood disorders Flashcards
What are the 4 stages of a clot formation?
1) vasocontriction 2) platelet plug formation 3) Coagulation 4) fibrinolysis
what occurs during the vasoconstriction stage of clot formation?
Diminishes blood flow and loss
What do platelet granules relase to induce vasoconstriction during clot formation?
Serotonin
What three factors occur to allow a platelet plug formation to occur?
1) collagen 2) ADP 3) Thromboxane A2
What does collagen do to help create a platelet plug?
Collagen promotes the platelets to adhere d/t vWF
What is vWF?
Von willebrand factor which is the portion of the platelet that causes adhering of the platelet to the damaged area
What does ADP do to help create a platelet plug?
ADP attracts more plateles
What does Thromboxane A2 do to help create a platelet plug?
thromboxane promotes aggregation, degranulation and vasoconstriction
what is the most common inherited bleeding disorder?
Von willebrand disease (lack of vWF)
What are the two pathways of the coagulation stage of a clot formation?
intrinsic (APTT) and extrinsic pathway (PT)
what happens in the fibrinolysis phase of the clot formation?
Plasminogen is activated by plasminogen activators (both nonfibrin-specific or less fibrin-specific) in order to degrade fibrinogen
What kind of condition occurs when fibrinolysis is compromised?
An emergency situation
what basic routine laboratory test categories can be used to evaluate the ability to form a clot?
1) vasocontriction 2) platelet plug formation 3) Coagulation
what basic routine laboratory tests can be used to evaluate the vasoconstriction ability to form a blood clot?
none
what basic routine laboratory tests can be used to evaluate the platelet plug formation ability to form a blood clot?
1) Platelet Count 2) Bleeding Time (BT)
what basic routine laboratory tests can be used to evaluate the coagulation ability to form a blood clot?
1) Prothrombin Time (PT) 2) (activated) Partial Thromboplastin Time (APTT, PTT)
Is blood clotting the same as coagulation?
No, coagulation is a phase of blood clotting
What category of basic laboratory test is used to evaluate the ability to remove a blood clot when it is no longer needed?
Fibrinolysis
What fibrinolysis category basic laboratory test is used to evaluate the ability to remove a blood clot when it is no longer needed?
Fibrin degradation products (FDP, D-dimer)
What type of test is a bleeding time?
primarily a platelet function test
What does the bleeding time evaluate?
Evaluates interaction of platelets with vessel wall and formation of the platelet plug
Does the bleeding time function dependent of coagulation or independent of coagulation?
functions independent of coagulation
What condition will prolong bleeding time?
Thrombocytopenia (<100K, definitely , 50K)
What must be established in order for a bleeding time to be used as a platelet function test?
a normal platelet count must first be established