blood clotting

what are the factors that keep platelets inactivated?

prostacyclin, Nitric oxide, endothelial ADPase

what is hemophilia what are its two major forms and what is the proportion of each form and what is it's cause of each form?

1) Bleeding disorder- Caused by a deficiency in one of two clotting factors: Factor VIII or Factor IX 2) hemophilia A- which accounts for 80% of all cases- deficiency in clotting factor VIII 3) Hemophilia B- deficiency in clotting factor IX

what are the basic steps that occur following damage to a blood vessel?

1) Damage to vessel stimulates clotting 2) vasoconsriction of blood vessel 3) platelets aggregate and form a plug 4) plug and surrounding infiltrated by web of fibrin 5) fibrin acculation forms clot 6) clot retraction brings together edges of the blood vessel wall at the point of injury to repair the damage

what are the two major pathways that form fibrin called, how do they differ, and what are the triggering factors for each pathway?

1) extrinsic and Intrinsic pathways 2)Differ in activators- --Extrinsic activators is: tissue thromboplastin; Factor VII activated Short pathway --Intrinsic Activator is: collagen, glass and others; Factors XII, XI, IX and VIII are activated Factor XII-> XI-> IX-> IXa-> prothomrin-> thrombin-> Fibrinogen-> fibrin

what is disseminated intravascular coagulation? what are the effects of this condition and how can a condition involving excessive clotting lead to hemorrhage?

1) localized coagulation in small vessels 2) triggered by systemic infections and certain blood cancers 3) results from: release of plasminogen activator inhibitor- prevents fibrinolysis; stimulation of both clotting pathways

What are platelets, what is their lifespan, and where are they made? where are they destroyed

1) small, regular shaped, clear cell fragments lacking a nucleus. 2) 5 to 9 days 3) they are made in the bone marrow and stored in the spleen 4) they are destoryed by thrombopoientin usually produced in the liver or kidneys

what are the 3 categories of drugs that are designed to interact with clotting mechanisms and how does each function?

Anticoagulates-Prevent clotting commonly called "blood thinners" anti-platelets- prevent clotting formation- commonly used to prevent heart attack and strokes Thombolytics- breakup already formed clots- Commonly call "clot busters"

What is fibrin and what is it's role in blood clotting?

Fibrin is a fiberous protein formed from fibrinogen by the action of thrombin. Becomes highly crosslinked and binds with platelets to form a clot.

what are the major types of anticoagulants and what is the mechanism of action for each?

Heparin- Acts by activating enzyme inhibitor antithrombin III (AT) activated (AT) then inactivates thrombin and other proteases involved in blood clotting, most notably factor Xa Warfarin- Acts by carboxylation and inactivation of factor VII and prothombin; affects both intrinsic and extrinsic clotting mechanisms Dibigatran-(pradaxa) Thrombin inhibitor Rivaroxaban- Factor X activation inhibitor apixaban- factor X activation inhibitor

what is Von Willbrand Disease, what are the symptoms and what is the cause?

Most common hereditary coagulation

what are the factors that lead to fibrin breakdown?

Plasmin

what are the factors that stimulate fibrin breakdown and what factors inhibit fibrin breakdown?

Stimulate: Tissue plasminogen Activator (tPA), enzyme urokinase, clotting factors XIa, XIIa, kalikrein Inhibit: Alpha- antiplasmin and alpha- macroglobulin; plasminogen activator inhibitor

what chemical regulates platelet formation and from where does it come?

Thrombopoientin comes from the liver or kidneys

what are the factors that activate platelets?

Von williebrand Factors

what are the two most commonly used antiplatelet drugs?

aspirin and clopidogrel (plavix)

What is thrombocytopenia and what are the major causes of it?

deficiency in platelets- Occurs when bone marrow makes to few platelets or when too many platelets are destoryed Major causes: leukemia, anemia, lymphomas, HIV

what are the two most commonly used thrombolytic drug? why is it important for both for the treatment of stroke and heart attack?

streptokinase plasminogen Activators --they break up clots that cause the problem