Final answer:
The 'lub-dub' sound of a heartbeat is caused by the closing of heart valves when the ventricles contract during systole and blood is pumped out which confirms the statement as true.
Step-by-step explanation:
The statement that the sound of a heartbeat results when the ventricles contract and blood is surged out of the heart is true. The heartbeat sounds, often described as 'lub-dub', occur due to the closing of the heart valves. The first sound, 'lub', is due to the closure of the atrioventricular (AV) valves when the ventricles contract during ventricular systole, sending blood into the pulmonary trunk and aorta. The second sound 'dub' occurs when the semilunar (SL) valves close following the ejection of blood from the heart.
When the ventricles contract, raising pressure within the ventricles, the AV valves are shut, preventing backflow to the atria, and the increase in pressure subsequently opens the SL valves allowing blood to be pumped out. This process is initiated by an electrical stimulation that starts at the SA node, leading to atrial contraction, followed by a pause at the AV node before the charge spreads through the ventricles causing them to contract and pump blood through the body.