Because of the double circulatory system, the blood travels around the body quickly
Parts of the heart
Left atrium
Right atrium
Left ventricle
Right ventricle
Valves
Heart
Organ consisting mainly of muscle tissue
Pumps blood around the body
The left side of the heart has a thicker muscle wall than the right because the left side has to pump blood around the whole body, not just to the lungs
The oxygen is used in respiration to provide energy for contraction
Sometimes the pacemaker cells stop working correctly so doctors implant an artificial pacemaker
Artificial pacemaker
A small electrical device that corrects irregularities in the heart rate
