Pulmonary embolism. A blood clot arrives at the heart and is sent, with the blood flow, towards the lungs. Being too big to circulate into the blood vessels, narrower and narrower, up to the pulmonary alveoles, this clot will obstruct certain pulmonary arterioles, provoking an ischemia then a pulmonary embolism. This image is part of a series on pulmonary pathologies. See. images 0447007 and 0447307 for the healthy lung, 0445407 and 0445507 for the normal pulmonary circulation (heart, lungs and vessels), 0447407 and 0447507 for a symbolic representation of pulmonary pathologies, 0445607, 0445707, 0447107 and 0447207 for the lung cancer, 0445807, 0443807, 0446107, 0446207, 0446907, 0447607 and 0447707 for pulmonary embolism, 0551407, 0551507, 0551607 and 0551707 for the tuberculosis.