Cardiovascular System

2. A small vein that collects blood from capillaries.
4. Relating to the lungs.
6. A blood vessel that carries blood away from the heart.
9. One of the two lower chambers of the heart.
10. Describes the relationship between the volume of blood filling the heart and the force of the heart’s contraction.
11. The largest artery in the body, carrying blood from the heart to the rest of the body.
13. A structure in the heart or veins that ensures blood flows in one direction.
14. The innermost layer of the heart wall.
16. A breathing technique that increases pressure in the chest, affecting heart and blood flow.
21. Specialized fibers in the heart that help coordinate contractions.
22. The muscular tissue of the heart.
23. The amount of blood ejected by a ventricle during a single heartbeat.
24. A small branch of an artery leading to capillaries.
26. One of the two upper chambers of the heart.

1. A blood vessel that carries blood toward the heart.
2. The narrowing of blood vessels.
3. The thickness or resistance to flow of blood.
5. The widening of blood vessels.
7. Large veins that carry deoxygenated blood to the heart.
8. The phase of the heartbeat when the heart muscle contracts and pumps blood out of the chambers.
12. The outermost layer of the heart wall.
15. The phase of the heartbeat when the heart muscle relaxes and allows the chambers to fill with blood.
17. A wall dividing two cavities, such as the heart’s chambers.
18. The sinoatrial node; the heart’s natural pacemaker.
19. The atrioventricular node; relays electrical impulses from the atria to the ventricles.
20. The protective sac surrounding the heart.
25. Electrocardiogram; a test that measures the electrical activity of the heart.