Images Dated 9th December 1996

Coloured SEM of red blood cells forming a clot

Blood clot. Coloured Scanning Electron Micrograph (SEM) showing the formation of a blood clot. Red blood cells (erythrocytes) are seen trapped by a sheet of protein material made of hundreds of tiny fibrin threads (blue). Fibrin is an insoluble protein which is essential in the arrest of bleeding. As the blood cells become trapped they will begin to lose their normal rounded shape. Blood clots form to repair blood vessels damaged by injury or disease. Abnormal clotting in blood vessels, as occurs in a thrombus in intact arteries and veins, is the principal cause of heart attack and stroke. Magnification: x2, 740 at 6x7cm size

© CNRI/SCIENCE PHOTO LIBRARY