The thinnest of the four chambers, is the left atrium. Firstly, the atria are thinner than the ventricles, simply because the ventricles need more pressure to pump the blood. read more
The heart is a two-stage electric pump with four chambers, describes Dr. Benjamin Wedro for MedicineNet. Deoxygenated blood returns to the heart, filling the right atrium and initiating the electrical impulse that generates a heartbeat. read more