text: Our heart is myogenic. That is it can beat on its own. If you take out your heart and put it in a solution with the right concentration of sodium, potassium and calcium, it can still beat. This is because, there are a group of cells known as the pacemakers in the SAN,AVN and Purkinjie fibres. They auto depolarise and start an electtrical impulse that travels down a certain pathway so that the 2 atria contracts before the 2 ventricles. \n\nHowever the rate of heart beat is controlled by the medulla of the brain. It either speeds up (sympathetic) or slows down (parasympathetic via vagus and glossopharyngeal) depending on the needs of the body.