It’s about the size of a fist and is well protected by the rib cage. It’s made of some of the cleverest muscles in your body – cardiac muscles! Cardiac muscles are pretty tough! Cardiac muscles contract and relax. The contracting and relaxing pushes blood all around your body. The cells in your cardiac muscle are programmed to do this contracting and relaxing, all by themselves, over and over again without you ever thinking about it! Find out more about the heart at: http://www.funkidslive.com/learn/hallux/heart-beat/ Subscribe for more videos like this! Fun Kids is the UK's children's radio station. Tune in on DAB Digital Radio across the UK, on mobile and online at http://www.funkidslive.com Professor Hallux’s Heart Beat is funded thanks to a Heart Research UK Health Heart Grant.