Cardiovascular System

3. – Vessels that return blood to the heart.
5. – Phase of the cardiac cycle when the ventricles contract and pump blood.
7. – Vessels that carry blood away from the heart.
9. – Internal wall dividing the right and left sides of the heart.
10. – Node in the right atrium known as the heart’s natural pacemaker.
11. – The two lower pumping chambers of the heart.
12. Type of circulation that carries blood to and from body tissues.
17. Sensors that detect changes in blood pressure.
20. tendineae – Tendon-like cords that anchor heart valves to the ventricles.
22. Circulation that carries blood to and from the kidneys.
23. Type of circulation between the heart and lungs.
24. – Microscopic vessels where exchange of materials between blood and cells occurs.
25. Hormone that increases heart rate during stress.
27. – The smooth inner lining of the heart chambers.
28. – Also called the bicuspid valve; located between the left atrium and left ventricle.
30. Hormone that helps regulate heart rate and metabolism.

1. – The outer surface layer of the heart wall.
2. – Phase of the cardiac cycle when the ventricles relax and the atria contract.
4. – Membrane that encloses and protects the heart.
6. Sensors that respond to oxygen and carbon dioxide levels in the blood.
8. – Valve located between the right atrium and right ventricle.
13. Circulation that supplies blood directly to the heart muscle.
14. – Fibers that carry impulses to the ventricular walls, causing contraction.
15. Part of the medulla that controls heart rate and blood vessel diameter.
16. Circulation delivering blood from digestive organs to the liver for nutrient processing.
18. Circulation supplying blood to the brain through the circle of Willis.
19. – The thick middle layer of cardiac muscle tissue.
21. – Semilunar valve leading from the left ventricle to the aorta.
26. – Semilunar valve leading from the right ventricle to the pulmonary arteries.
29. – The two upper receiving chambers of the heart.