The heart sits in the middle of the chest behind the sternum, and extends towards the left side. It is a strong muscular pump, about the size of its owner’s clenched fist. It has four chambers:
- two atria, which receive blood to pump to the ventricles
- two ventricles, one that pumps blood to the lungs (right), and another that pumps blood to the body (left)
In the average adult, the heart beats around 60 – 100 times per minute, sending about six litres of blood through well over 1,000 complete circuits of the body each day.
During a lifetime of 70 years, the heart will beat more than 2.5 billion times. The only rest it gets or needs is a split-second pause between beats.
Read more: Anatomy of the Heart
Source: learncpronline