One moment, please http://siulodarba.com/research-paper-on-alzheimers curiously delve essays on school uniforms concerned wave Although Leonardo’s interest in anatomy was not unique among artists, his scalpel-sharp observation, coupled with the lucid presentation of his findings, set him apart from his peers. “Towards the end of his life, Leonardo was obsessed with the structure and functioning of the valves of the heart,” says Clayton. “So he made a glass model of the aortic valve, through which he pumped grass seeds suspended in water. And he witnessed little circular vortices in what’s called the sinus of Valsalva, a sort of swelling at the root of the aorta. When blood flows through, these vortices play a role in closing the aortic valve. This is something that wasn’t observed again until the 20th century – and Leonardo posited it in 1513.”