Confocal micrograph of a stimulated mast cell that has just exploded releasing numerous histamine granules. The remains of the cell are seen towards the lower left, still containing a number of granules that have not escaped. This occurs during an allergic response leading to smooth muscle contraction and increased permeability of the blood vessels.
B0002677 Mast cell releasing histamine granules. Wellcome Images available under the following creative commons usage http://creativecommons.org/licenses/by-nc-nd/2.0/uk/