Summary
Highlights
Oxygenated blood returns from the lungs to the left atrium (chamber 3) then passes through the mitral valve into the left ventricle (chamber 4). The mitral valve, like other heart valves, ensures unidirectional blood flow.
Finally, from the left ventricle, blood goes through the aortic valve and into the aorta, which distributes oxygenated blood to the rest of the body. This continuous cycle of blood flow through the four chambers of the heart occurs every moment of every day.
From the right ventricle, blood passes through the pulmonary valve into the pulmonary arteries, which carry it to the lungs. Pulmonary arteries are unique as they carry deoxygenated blood away from the heart. In the lungs, the blood releases carbon dioxide and picks up oxygen, changing from 'blue' (deoxygenated) to 'red' (oxygenated).
The heart, an amazing organ, functions as a powerful pump, working tirelessly from the fetal stage until death. Understanding its internal structure is key to comprehending its function.
Blood from all parts of the body returns to the heart via veins. Blood from the arms and head converges into the superior vena cava, while blood from the legs and belly flows into the inferior vena cava. Veins are defined as vessels carrying blood towards the heart.
After being pumped by the heart, blood leaves via arteries. The aorta is the largest artery, forming an arch (aortic arch) that branches off to supply blood to the arms and head before descending to the rest of the body. Arteries are vessels carrying blood away from the heart, a concept easily remembered as both start with 'A'.
Deoxygenated blood from the superior and inferior vena cava enters the right atrium (chamber 1). It then passes through the tricuspid valve into the right ventricle (chamber 2). Valves, like the tricuspid valve, ensure blood flows in one direction, preventing backflow.