What is Haemostasis?Haemostasis is the human body’s response to blood vessel injury and bleeding. It involves a co-ordinated effort between platelets, endothelial cells, blood clotting factors including ‘tissue factor’, which results in blood clot formation.1 Achieving haemostasis helps control blood loss and the release of growth factors.

Stages of Haemostasis

Primary Haemostasis

1. Vaso-constriction to minimise blood loss by reducing blood flow to the site of damage.2. Damaged endothelial cells locally activate platelets.3. Platelet adhesion to damaged endothelium.4. Adhered platelets activate other nearby platelets.5. Activated platelets become sticky, fuse together with adhered platelets, forming a platelet plug.

Secondary Haemostasis - Coagulation cascade

1. Activated platelets in the platelet plug trap red blood cells.2. Fibrin strands form, strengthening the clot.3. Ca2+ ions, also known as clotting factor IV, are essential in several stages of the coagulation cascade.4. Further factors released during coagulation cascade include growth factors for tissue repair.