The correct order of flow of blood from the coronary sinus to the lung capillaries is:
- Coronary sinus
- Right atrium
- Tricuspid valve
- Right ventricle
- Pulmonary valve
- Pulmonary trunk
- Left atrium
- Mitral valve
- Left ventricle
- Aortic valve
- Aorta
- Pulmonary arteries
- Lung capillaries
The journey of blood from the coronary sinus to the lung capillaries highlights the remarkable efficiency of the cardiovascular system. Starting in the heart, blood from the coronary sinus, which drains the heart muscle itself, empties into the right atrium. This thin-walled chamber serves as a temporary reservoir before the blood passes through the tricuspid valve into the muscular right ventricle. Here, the powerful right ventricle contracts, pumping the deoxygenated blood through the pulmonary valve and into the expansive pulmonary trunk. This trunk branches into left and right pulmonary arteries, which deliver the blood to the numerous capillaries within the lungs.
In these delicate lung capillaries, a vital exchange occurs. Oxygen from the inhaled air diffuses across the thin capillary walls, replacing the carbon dioxide carried by the blood. This oxygenated blood, now a bright red color, collects in the pulmonary veins and travels back to the heart, ultimately reaching the left atrium.
Once again, a valve, the mitral valve, opens to allow the blood to enter the left ventricle, the strongest chamber of the heart. With a powerful contraction, the left ventricle propels the oxygen-rich blood through the aortic valve and into the aorta, the largest artery in the body. From here, the blood branches out to all corners of the body, delivering oxygen and nutrients to every cell. This intricate journey, completed in a matter of seconds, underscores the seamless coordination between heart, lungs, and blood vessels to sustain life.