Here's how platelets form clots. This small artery has a cut. Blood flowing past the cut includes red blood cells that carry oxygen, platelets that come from white blood cell fragments, and clotting factors that help blood clot. When a blood vessel is damaged, blood cells and plasma ooze into surrounding tissue. Platelets immediately stick to the edges of the cut and release chemicals that attract more platelets. Eventually, a platelet plug is formed, and the outside bleeding stops.
On the inside, clotting factors cause a cascade of activity that includes strands of blood-borne material called fibrin sticking together to seal the inside of the wound. Eventually, the blood vessel heals, and several days later, the blood clot dissolves.
Review Date 2/2/2023
Updated by: Mark Levin, MD, Hematologist and Oncologist, Monsey, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.