2.51 Flashcards
what is trombomodulin
a glycoprotein present on endothelial cells that combines with thrombin
what does the Thrombomodulin-thrombin complex activate
protein C
what does protein C and its cofacfor, Protein S degrade
factors V and VIII
what is antithrombin III
a glycoprotein that binds to and subsequently inhibits factor X and thrombin
where is antithrombin III produced
The liver
what does Heparin cofactor II inhibit
Thrombin (least important of the three)
where is Heperin cofactor II produced
The liver
what initates the breakdown of blood clots
Plasmin (inactive form plasminogen)
what is plasminogen activator (t-PA)
converts plasminogen to plasmin
how does plasmin break down clots
plasminogen is caught in the clot, over several days, it is activated and breaks down the fibrin mesh
what are four fibrinolysis inhibitors
- plasminogen activator inhibitor 1
- plasminogen activator inhibitor 2
- alpha2-antiplasmin
- alpha2-macroglobulin
what is petechia
pinpoint hemorrhages on skin and mucous membranes (caused by low platelets)
what are coagulation tests used for
to determine the function of intrinsic and extrinsic components of the coagulation system
what is inside the tube of the coagulation test
sodium citrate (binds calcium, prevents clots)
what is prothrombin time (PT) used to asses
the extrinsic pathway, calcium as added to plasma, and thromboplastin is added to substitute for tissue factor.
what is the international normalized ratio
was devised to standardize results between with manufacture with PRO-TIME
waht is an INR (international normalized ratio) most often used to monitor
the effectiveness of drugs such as warfarin (coumadin)
why must anticoagulants be carefully monitored
maintain the balance between preventing clots and causing excessive bleeding
what is the average time is takes for coagulation in the PRO-TIME test
10-15 seconds
what is the normal INR range
2.0 - 3.0 for basic blood thinning needs
what must the INR be for patients with clotting risks
about 2.5 to 3.5
what is used to asses the intrinsic pathway
activated partial thromboplastin time (APTT)
what is used in APPT
calcuim is added to plasma to replace what was removed by citrate,
Kaolin and phospholipids are added to substiture for contact factor
how long does clotting take with APTT
25-36 seconds
