Circulation through the Heart
Key Point:
- The cardiovascular system ensures delivery of oxygen and nutrients to the body tissues and removal of waste, notably carbon dioxide, from the body tissues.
Path of blood flow through lungs, heart, and body:
1. Within the lungs, blood picks up oxygen.
2. Travels through pulmonary veins to left atrium.
3. From the left atrium, oxygen-rich blood passes through the left atrioventricular valve, then enters the left ventricle.
4. The left ventricle pumps this blood through the aortic semilunar valve and into the aorta, which is the major systemic artery.
5. From the aorta, oxygen-rich blood is distributed via systemic arteries to the body tissues.
6. Oxygen moves out of the bloodstream and into the body tissues, and,
Metabolic waste, including carbon dioxide, move into the blood.
7. Systemic veins carry the oxygen-poor blood away from body tissues,
and drain into the superior and inferior vena cavae.
8. The superior and inferior vena cavae drain directly into the right atrium of the heart.
9. From the right atrium, blood passes through the right atrioventricular valve, and into the right ventricle.
10. The right ventricle contracts and pumps the blood past the pulmonary semi-lunar valve, and into the pulmonary trunk, which splits to form the left and right pulmonary arteries.
11. The pulmonary arteries carry the oxygen-poor blood to the lungs, where carbon dioxide is released and the blood is re-oxygenated; from here, the re-oxygenated blood enters the pulmonary veins, and the cycle continues.