| A | B |
|---|
| cardiovascular system | The body system that consists of the heart, blood vessels, and blood, and that carries needed substances to cells and carries waste products away from cells |
| heart | A hollow, muscular organ that pumps blood throughout the body |
| atrium | Each of the two upper chambers of the heart that receives blood that comes into the heart. |
| ventricle | A lower chamber of the heart that pumps blood out to the lungs and body |
| valve | A flap of tissue in the heart or a vein that prevents blood from flowing backward. |
| pacemaker | A group of cells located in the right atrium that sends out signals that make the heart muscle contract and that regulates heartbeat rate |
| artery | A blood vessel that carries blood away from the heart |
| capillary | A tiny blood vessel where substances are exchanged between the blood and the body cells |
| vein | A blood vessel that carries blood back to the heart |
| aorta | A blood vessel that carries blood back to the heart |
| force | A push or a pull exerted on an object |
| coronary artery | An artery that supplies blood to the heart itself. |
| diffusion | The process by which molecules move from an area in which they are highly concentrated to an area in which they are less concentrated. |
| pressure | The force that something exerts over a given area |
| blood pressure | The pressure that is exerted by the blood against the walls of blood vessels |
| sphygmomanometer | An instrument that measures blood pressure |
| plasma | The liquid part of blood |
| red blood cell | A cell in the blood that takes up oxygen in the lungs and delivers it to cells elsewhere in the body |
| hemoglobin | An iron-containing protein that binds chemically to oxygen molecules and makes up most of a red blood cell |
| white blood cell | A blood cell that fights disease |
| platlet | A cell fragment that plays an important part in forming blood clots |
| fibrin | A chemical that is important in blood clotting because it forms a net of tiny fibers that traps red blood cells |
| blood transfusion | The transference of blood from one person to another |
| lymphatic system | A network of veinlike vessels that returns the fluid that leaks out of blood vessels to the bloodstream |
| lymph | The fluid that the lymphatic system collects and returns to the bloodstream |
| lymph node | A small knob of tissue in the lymphatic system that filters lymph. |
| atheroscerosis | A condition in which an artery wall thickens as a result of the buildup of fatty materials |
| heart attack | A condition in which blood flow to a part of the heart muscle is blocked, which causes heart cells to die |
| hypertension | A disorder in which a person’s blood pressure is consistently higher than normal |
