CBSE Class 10 Answered

In humans, the cardiac movements are mainly due to stimuli originating in the heart muscle itself. The heart does not act solely in response to nervous stimulation. So the heartbeats occur in ordered rhythmic manner due to inherent properties of cardiac muscle. The normal heart activities are autoregulated by specialised muscles called nodal tissue. Hence the human heart is called myogenic. Myogenic heart has a pace maker system. There is a pacemaker of specialized cardiac muscles situtated in the right auriclular wall, also called SA node. It sends impulse which goes to the AV node and then to the bundle of HIs and Purkinje fibres to complete a cardiac cycle.