Check out this gorgeous image - a colorized scanning electron micrograph - of a blood clot. Red blood cells are shown in red; leukocytes are green; platelet aggregates are gray; and the thread-like brown stuff is fibrin, the protein that holds blood clots together. The image comes from the University of Pennsylvania School of Medicine, where new findings show how fibrin behaves in blood clots.
Image by John Weisel, University of Pennsylvania School of Medicine
