UPSC 2017 CDS I GK Paper

The mammalian heart is myogenic and it is regulated by nerves. The heartbeat originates from sinoatrial node. The impulse starts in a small bundle of specialised cells located in the right atrium, called the sinoatrial node. The electrical activity spreads through the walls of the atria and causes them to contract. This forces blood into the ventricles. The sinoatrial node sets the rate and rhythm of our heartbeat.