Take a peek inside the heart? In this virtual journey through the heart, we see the bicuspid (mitral valve), tendinous filaments, papillary muscles and the aortic (semilunar) valve. We can also spot the sinuses of Valsalva - located behind the sinuses of the aorta, just behind the semilunar cusps, from which the right and left coronary arteries (the blood supply to the heart) begin.