Blood cells. Scanning electron micrograph (SEM) of three types of blood cell. They are: red blood cells (erythrocytes,red),white blood cells (lymphocytes,blue) and platelets (thrombocytes,pink). The platelets are within a mesh of fibrin (light brown),the protein that traps blood cells at a wound,forming a clot. Platelets are membrane bound cell fragments from the bone marrow which cause fibrin to form at wounds. Red blood cells carry oxygen around the body,their biconcave shape providing a maximum surface area for the exchange of gases. White blood calls are a vital part of the immune system. Magnification: x4,500 at 5x7cm size. x15,400 at 6.5x9.5ins |