Understanding Blood Flow: Heart & Lungs Oxygenation Process

Pathway of blood flow through the heart and lungs to obtain oxygen (pulmonary circulation)

1. Deoxygenated blood from the body: Blood that has been depleted of oxygen during its journey through the body's tissues returns to the heart via the superior vena cava (which carries blood from the upper body) and inferior vena cava (which carries blood from the lower body).

2. Right atrium: The deoxygenated blood enters the right atrium, which is the first chamber of the heart.

3. Tricuspid valve: From the right atrium, the blood passes through the tricuspid valve into the right ventricle.

4. Right ventricle: The right ventricle contracts, pumping the deoxygenated blood into the lungs through the pulmonary artery.

5. Pulmonary arteries: The pulmonary arteries carry the deoxygenated blood to the lungs.

6. Lungs: In the lungs, the blood is exposed to oxygen and carbon dioxide is released. The oxygen binds to hemoglobin in the red blood cells.

7. Pulmonary veins: Oxygenated blood now leaves the lungs and returns to the heart via the pulmonary veins.

8. Left atrium: The oxygenated blood enters the left atrium, which is the second chamber of the heart.

9. Mitral valve: From the left atrium, the blood flows through the mitral (bicuspid) valve into the left ventricle.

10. Left ventricle: The left ventricle contracts, pumping the oxygenated blood out to the body via the aorta.

11. Aorta: The aorta carries the oxygenated blood to all parts of the body through its branches.

This completes the pulmonary circulation, the process by which deoxygenated blood is transported to the lungs for oxygenation and then returned to the heart and pumped out to the body's organs and tissues.