1. Cardiovascular System Key Terms 7 th Grade Science

2. Cardiovascular System The body system that consists of the heart blood vessels and blood that carries needed substances to cells and carries waste products away from cells

3. Heart A hollow muscular organ that pumps blood throughout the body

4. Atrium Each of the two upper chambers of the heart that receives blood entering the heart

5. Ventricle A lower chamber of the heart that pumps blood out to the lungs and body

6. Valve A flap of tissue in the heart or a vein that prevents blood from flowing backwards

7. Pacemaker A group of cells located in the right atrium that send out signals that make the heart muscle contract and that regulates heart rate

8. Artery A blood vessel that carries blood away from the heart

9. Capillary A tiny blood vessel where substances are exchanged between the blood and body cells

10. Vein A blood vessel that carries blood back to the heart

11. Aorta The largest artery in the body

12. Coronary artery An artery that supplies blood to the heart

13. Blood pressure The pressure the is exerted by the blood against the walls of blood vessels

14. Diffusion The process by which molecules move from an area in which they are more concentrated to an area in which they are less concentrated

15. Plasma The liquid part of the blood

16. Red blood cells A cell in the blood that takes up oxygen in the lungs and delivers it to cells elsewhere in the body

17. Hemoglobin An iron containing protein that binds chemically to oxygen molecules and makes up most of a red blood cells

18. White blood cell A blood cell that fights disease

19. Platelet A cell fragment that plays an important part in forming clouts

20. Arteriosclerosis A condition in which an artery wall thickens as a result of a build up of fatty materials

21. Heart attack A condition in which blood flows to a part of the heart; the heart muscle is blocked which causes heart cells to die

22. Hypertension A disorder in which a person’s blood pressure is constantly higher than normal