The "beat" of your heart is the contraction of the right and left ventricles.
The right atrium passes blood from the body into the right ventricle -- when the ventricle contracts, it forces shut the valve leading back to the atrium, and the blood is pushed into the pulmonary arteries that lead to the lungs.
The blood returns from the lungs to the left atrium, and flows into the left ventricle. When the left ventricle contracts, the blood is pushed out of the ventricle into the aorta, the body's main artery, to be carried through the arterial system to the various parts of the body.
Purkinje Fibers actually makes the ventricles contract.
The ventricles contract.
If the papillary muscles fail to contract the valves will prolapse. The papillary muscles are located in the ventricles and contract to prevent prolapse.
When relaxed, the atria expand, and then the ventricles contract.
Not really sure what you mean by the base, the ventricles contract from the Apex (which is at the bottom) upwards.
The pulmonary artery and the aorta lead upward and away from the ventricles. Since the ventricles contract from the bottom, blood is more efficiently pushed out of the heart.
Yes, atria contracts before the ventricles.
Systole
Into the heart
contract
As the ventricles of the heart contract the pressure in the ventricles rises beyond that of the atria. This pressure differential causes the AV valves to shut.
The right ventricle pumps blood to the lungs.