Haemostasis
Vascular injury
- Intact endothelial cells in proximity to disrupted endothelium release arachidonic acid by phospholipase A2.
- cyclooxygenase-1 (COX-1 aka prostaglandin H synthase-1) converts arachidonic acid into thromboxane A2 in platelets
- Thromboxane stimulates platelet aggregation
- prostacyclin (PGI2) is a vasodilator produced from COX-2, stimulated by normal laminar flow