The above cycle traces blood as it passes in the un-oxygenated state from the vena cava through the heart to the...
The blanks in your question should be filled in as follows:
I. Vena cava
The above cycle traces blood as it passes in the un-oxygenated state from the vena cava through the heart to the lungs. In the lungs the blood is oxygenated, then passes through the left heart where it is pumped through the aorta to the rest of the body. As oxygenated blood leaves the heart into the aorta it also passes into the openings of the coronary arteries (ostia which are located in the cusps of the aortic valve), providing oxygen to the heart itself. Thus, there are pulmonary (lung), cardiac and systemic segments of the circulatory system.
Starting with deoxygenated blood in the vena cavae, the structures in order of blood flow is as follows:
1. Superior and Inferior Vena Cavae
2. Right Atrium
3. Tricuspid Valve
4. Right Ventricle
5. Pulmonic Valve
6. Pulmonary Artery
7. Right and Left Main Pulmonary Arteries
8. Pulmonary circulation (pulmonary arteries, arterioles, capillaries, venules and veins)
9. Right and Left Pulmonary Veins
10. Left Atrium
11. Mitral Valve
13. Left Ventricle
14. Coronary Circulation (left and right coronary arteries and left circumflex artery)
15. Ascending Aorta
16. Aortic Arch
17. Large arteries to upper body
18. Descending Aorta
19. Lower Thoracic Aorta
20. Abdominal Aorta
21. Large Arteries to lower body
22. Organ vascular beds (arteries, arterioles, capillaries, venules, veins)
23. Superior and Inferior Vena Cavae
And so on, as the cycle repeats.
As opposed to the systemic circulatory system (which provides blood to all organs other than the heart), the coronary system provides blood to the heart itself. The right and left coronary arteries arise as openings at the base of the right and left cusp of the aortic valve in the form of ostia…the right and left coronary ostia. The left main coronary artery gives off the left anterior descending (LAD) coronary artery with passes down along the anterior aspect of the left ventricle. It also gives rise to the left circumflex coronary artery that passes posteriorly. The right main coronary artery passes around the right upper portion of the heart and gives rise to the posterior descending branch that passes down the posterior aspect of the right ventricle.
The commonest sites of coronary artery occlusion (obstruction) leading to heart attacks are the proximal right coronary artery (usually s few centimeters from the right coronary ostium), and the proximal LAD (usually about one or two centimeters below or distal to the LAD’s origin from the left main coronary artery). Coronary occlusions occur at the sites where there has been a build-up of arteriosclerotic plaque. They can be from coronary thrombosis (clotting at the plaque site) or spasm of the vessel.
Systemic Circulation: As opposed to the coronary circulation the systemic circulation constitutes the circulation to the entire body other than the heart. It begins after the aortic valve where blood has left the heart, and ends in the superior and inferior vena cavae that bring deoxygenated blood from the organs back to the heart.
The heart pumps blood through the lungs to become oxygenated, then through the coronary circulation to supply oxygen to the heart itself, then through the systemic circulation to supply the entire remainder of the body.