Drugs affecting the blood

process of stopping blood flow

• 1. Collagen exposed due to damage, initiating effects
• 2. Receptors on platelets bind thrombin, thromboxanes and exposed collagen
• 3. platelets (change shape) activated when receptors are bound
• 4. results in release of granules containing ADP, TXA₂, 5-HT, PAF, & thrombin from platelets 
• 5. Chemicals bind to receptors of nearby platelets
• 6. aggregation occurs as a result of increased Ca²⁺ 
• 7. Increased Ca²⁺ 
• 8. TXA₂ synthesis; from arachadonic acid released from platelet
• 9. more TXA₂ released

thrombin comes from prothrombin, thrombin catalyzes reaction of fibrinogen to fibrin, which is used in binding platelets to form a platelet plug (blood clot)

lengthen time in forming clot and prevent thrombi from growing larger

• 1. Inhibits arachidonic acid to prostaglandin (prevents TXA₂ synthesis) 
• 2. lasts for the life of platelet
• 3. active site of enzyme is blocked by aspirin