# data[].attributes.body
After the gaseous exchange, the blood enter the heart again. The atrium   is relaxed while the ventricle is in the state of isovolumetric relaxation. The AV and semilunar valve is closed thus producing the second sound of the heart, the 'dub' sound

# data[].attributes.body
The atrium relaxed meanwhile isovolumetric contraction occurs for ventricular state. The AV valves are closed and the first sound 'lub' is produced. The semilunar valve remain close.

# data[].attributes.body
Deoxygenated blood is ejected through pulmonary artery from the heart. Meanwhile oxygenated blood is pumped through the aorta and pulmonary vein to the whole part of the body and also to the lungs.

# data[].attributes.body
Atrial contraction
The atrium is contracting and the ventricle is in the state of relaxed filling. The AV valves open to let the blood flows to the ventricle and the semilunar valve remained close

# data[].attributes.body
Deoxygenated blood and oxygenated blood enter both atria.

# data[].attributes.body
Passive filling

# data[].attributes.body
Ventricular isovolumetric contraction