EXPLANATION IN BRIEF :-
1. Blood flows from the lungs to the heart through the pulmonary veins. This blood is rich in oxygen (O2) and low in carbon dioxide (CO2).
2. The oxygen-rich blood enters the left atrium of the heart.
3. From the left atrium, the blood flows into the left ventricle.
4. When the left ventricle contracts, it pumps the oxygenated blood into the aorta, which is the largest artery in the body.
5. The aorta branches into smaller arteries, which carry oxygenated blood throughout the body's tissues and organs.
6. In the body's capillaries, oxygen is delivered to cells, and carbon dioxide (CO2) is picked up from the cells.
7. Oxygen-depleted blood, now rich in carbon dioxide, returns to the heart through the veins.
8. This deoxygenated blood enters the right atrium of the heart.
9. From the right atrium, it flows into the right ventricle.
10. The right ventricle contracts, sending the deoxygenated blood into the pulmonary artery.
11. The pulmonary artery carries this blood back to the lungs.
12. In the lungs, carbon dioxide is removed from the blood, and oxygen is replenished through the process of respiration.
This cycle repeats as the heart continuously pumps oxygenated blood to the body and receives deoxygenated blood from the body to send it back to the lungs for oxygenation.