Final answer:
Blood circulates through the heart in two loops: the right side loop takes oxygen-poor blood from the body to the lungs, while the left side loop distributes oxygen-rich blood to the body. Valves ensure one-way flow, and the process is driven by the rhythmic contractions of cardiomyocytes.
Step-by-step explanation:
Blood flows through the heart in a consistent and controlled way, ensuring that oxygen-rich blood is distributed to the body and oxygen-poor blood is sent to the lungs for reoxygenation. This process involves two main loops within the heart, commonly referred to as the "left side loop" and the "right side loop." Starting with the right side loop, oxygen-poor blood enters the right atrium from the body and is then pumped into the right ventricle. From there, it is pushed into the lungs, where it releases carbon dioxide and picks up oxygen.
Following the left side loop, the now oxygen-rich blood returns to the left atrium, moves into the left ventricle, and is then pumped to the rest of the body. The heart's valves ensure that blood flows in only one direction, preventing any backflow that could disrupt this vital circulatory process. This cyclical movement of blood is driven by cardiomyocytes, which are muscle cells that contract rhythmically and involuntarily, coordinated by electrical impulses starting at the sinoatrial node (SA node). Following the heart's contractions, blood is circulated throughout the body by a complex network of arteries and veins, where its flow and pressure are regulated by smooth muscle movement, skeletal muscle action, and one-way valves.