Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Pharm BMED 575
Hemostasis
| Question | Answer |
|---|---|
| What is the initial step in hemostasis? | Vasospasm (vascular constriction) |
| What is the second stage of hemostasis? | Platelet adhesion, activation and aggregation |
| What is the final step of hemostasis? | Fibrin formation and reinforcement of the platelet plug. |
| What are the three phases in hemostasis? | vascular, platelet and coagulation |
| What initiates the immediate smooth muscle contraction of a vasospasm? | exposure to plasma |
| What chemical released by platelets contributes to vasospasm? | thromboxane A2 |
| What chemical produced by intact endothelium is so short acting that disruption of its continuous production contributes to vasospasm? | the vasodilator nitric oxide |
| Describe how serotinin contributes to vasospasm | (notes aren't clear, need to look in book) |
| Name three substances produced by the endothelium that contribute to inhibition of clotting | Nitric oxide, heparin sulfate, PGI2 |
| Name three circulating factors that inhibit the clotting cascade | antithrombin (ATIII), protein C and S, TFPI |
| What is TFPI | tissue factor pathway inhibitor |
| Does TFPI reduce clotting or reduce bleeding? | TFPI contributes to hemostasis by inhibiting excessive clotting |
| What precursor is PGI2 a metabolite of? | arachidonic acid |
| Where is PGI2 produced? | endothelial cells |
| What function does PGI2 have? | inhibits platelet aggregation and secretion |
| Is PGI2 a procoagulant? | No, PGI2 acts to inhibit clotting on the interior of the vascular system |
| Where does nitric oxide come from | NOS (nitric oxide synthase) in EC |
| What effect does NO have? | vasodilation and platelet inhibition |
| What role does antithrombin play? | ATIII inhibits activated clotting factors |
| EC produce what compound that accelerates the activity of ATIII | heparin sulfate |
| Protein C is a plasma zymogen or cofactor? | zymogen |
| Protein S is plasma zymogen or cofactor? | cofactor |
| What role does protein C and S play in hemostasis? | they degrade Va and VIIIa |
| How do protein C and S work and where | The activity of protein C and S rely on the presence of thrombin at the thrombomodulin docking site at the EC |
| Where is TFPI found? | tissue factor pathway inhibitor is a circulating antithrombotic (reduces clotting) plasma protein |
| What portion of the plasma is TFPI found? | the lipoprotein fraction |
| Who does TFPI act on? | binds and inhibits Xa |
| What stimulates platelets to create a clot? | exposed collagen |
| what do platelets that have adhered to exposed collagen release? | activated platelets release thromboxane A2 and ADP |
| What receptor plays a role in platelet adhesion? | GPIIb/IIIa |
| what stimulates fibrinogen to convert to fibrin? | thrombin |
| What stimulates prothrombin to convert to thrombin? | Xa |
| Protein C in the presence of thrombin at the thrombomodulin site on EC converts to protein C (act), what clotting factors does protein C (act) down regulate? | XIa, IXa, Xa |
| what factors are inhibited by heparin? | VIIa, XIa, IXa, Xa and most importantly IIa |
| Where do oral anticoagulants work? | decrease production of zymogens II, VII, IX and X |
| What drug does the aPTT monitor? | heparin |
| What pathway is aPTT specific for? | the intrinsic pathway |
| Why is a protime specific for warfarin dosing? | Because only warfarin affects factor VII production |
| What pathway is the PT/INR specific for? | extrinsic |
| what activity does plasmin accomplish? | Plasmin breaks down fibrin |
Created by:
lisamccunesSS
Popular Medical sets