Our blood can’t afford to hang around. Besides its high-speed job of carrying oxygen and virus-killing cells around the body, lingering for too long in one place – such as in our leg vessels during a long plane flight – increases the risk of clotting. This computer simulation shows a slice through a virtual blood clot. Each red ball is a blood cell stuck to its neighbours with a glue-like chemical called fibrin (grey rods, magnified top right). Anti-clotting drugs often aim to dissolve fibrin, wearing down a clot. Yet the bloodstream itself can have a dramatic impact, dislodging huge chunks from the clot shown in the lower images with its turbulent current. Balancing this powerful physical force with the eroding effects of drugs is vital to disperse clots safely: into small enough pieces that won’t block up vessels supplying the lungs or brain as they float off downstream.
Written by John Ankers