To trace the flow of human blood?

The Pulmonary Circuit

1. Right Atrium: Deoxygenated blood from the body enters the right atrium through the superior vena cava (which receives blood from the head and upper body) and the inferior vena cava (which receives blood from the lower body).

2. Tricuspid Valve: The tricuspid valve opens, allowing blood to flow from the right atrium into the right ventricle.

3. Right Ventricle: The right ventricle contracts, pumping the deoxygenated blood through the pulmonary valve and into the pulmonary artery.

4. Pulmonary Artery: The pulmonary artery carries the deoxygenated blood to the lungs.

5. Lungs: In the lungs, the deoxygenated blood is oxygenated and the oxygenated blood returns to the heart via the pulmonary veins.

The Systemic Circuit

6. Left Atrium: Oxygenated blood from the lungs enters the left atrium through the pulmonary veins.

7. Mitral Valve: The mitral valve (also known as the bicuspid valve) opens, allowing blood to flow from the left atrium into the left ventricle.

8. Left Ventricle: The left ventricle contracts, pumping the oxygenated blood through the aortic valve and into the aorta.

9. Aorta: The aorta is the largest artery in the body and carries the oxygenated blood to all tissues and organs.

10. Arteries: The arteries branch off from the aorta and carry oxygenated blood to the tissues and organs.

11. Capillaries: The smallest blood vessels are the capillaries, where the exchange of oxygen, carbon dioxide, and other nutrients takes place between the blood and the tissues.

12. Veins: The veins collect deoxygenated blood from the tissues and organs and return it to the heart via the superior and inferior vena cava.

This cycle of blood flow is continuous and never stops. It ensures that all the tissues and organs in the body receive the oxygen and nutrients they need to function properly.