The exodus was a journey that moses had lead his people out of. To the Hebrews the release from slavery proved that God was protecting and watching over them.
The left and right ventricles are stronger pumps. The left ventricle is the strongest because it has to pump blood out to the entire body. When your heart functions normally, all four chambers work together in a continuous and coordinated effort to keep oxygen-rich blood circulating throughout your body.
The heart pumps blood in a two-step process. The atria pump blood into the ventricles and then the ventricles pump blood out of the heart. Chambers of the heart fill with blood during a relaxation phase (diastole) and eject blood during a contraction phase (systole). Atrial systole precedes ventricular systole.