The Heart

2. the valve between atrium and ventricle, preventing backflow of blood into the atrium when the ventricle contracts.
5. the right atrioventricular valve
7. A small mass of specialized cardiac muscle fibers located in the wall of the right atrium of the heart that acts as a pacemaker by generating at regular intervals the electric impulses of the heartbeat
8. left upper chamber of the heart, receiving blood via a vein.
10. Relays cardiac impulses to the ventricular cells causing the ventricles to contract.
12. artery carrying deoxygenated blood from the heart to the lungs
14. left lower chamber of the heart passing blood to an artery
15. main vein carrying deoxygenated blood from the body to the heart: superior from the head and neck, inferior from the rest of the body.

1. main artery carrying oxygenated blood from the heart to the rest of the body
2. a node of specialized heart muscle located in the wall of the right atrium; receives impulses from the sino atrial node and transmits them to atrioventricular bundle
3. right lower chamber of the heart passing blood to an artery
4. cardiac muscle wall separating the left and right sides of the heart.
6. attached to the atrioventricular valves to stop them turning inside out when the ventricles contract.
7. valves at the base of the arteries leaving the heart that prevent the backflow of blood into the ventricles when they relax.
9. vein carrying oxygenated blood back to the heart from the lungs
11. the left atrioventricular valve
13. right upper chamber of the heart, receiving blood via a vein.