1. The heart is simply a pump, which circulates blood throughout the body.2. Tubes called blood vessels carry it from the heart to all parts of the body and back again.3. The heartbeats can be felt as the pulse where certain arteries lie just beneath the skin, and the most well – known place where this occurs is at the wrist.4. The heart consists of two chambers, left and right, separated from each other by a wall.5. Each chamber is further divided into upper and lower compartments, which communicate with each by valves.6. Each upper compartment is called an atrium.7. Heart failure, or cardiac arrest, means that the heart has stopped beating.8. The heart can be made to beat artificially by rhythmically applying pressure to the chest.9. When pressure on the chest has been relaxed, blood returns to the heart again.