external features of the heart

• In a human, the heart lays just off-centre towards the left of the chest cavity. the main part of the heart consists of cardiac muscle. there are two main pumping chambers called the ventricles and atria.
• lying over the surface of the heart are coronary arteries that supply oxygenated blood to the cardiac muscle. as the heart is a hardworking organ, the coronary arteries are very important. if the coronary arteries become blocked, they will restrict oxygen access to the heart muscle which causes death to tissue, angina or heart attacks.