| A | B |
|---|
| artery | a blood vessel that carries blood away from the heart |
| atrium | either of the two upper chambers of the heart that receives blood from veins |
| blood vessel | a tube in the body through which blood flows |
| capillary | a tiny blood vessel |
| circulatory system | the body system that includes the heart, blood vessels, and blood |
| heart | the muscular organ that pumps blood throughout the body |
| platelet | a small blood cell that helps the blood to clot |
| pulmonary artery | the artery that carries blood from the right ventricle to the lungs |
| pulmonary vein | the vein that carries blood from the lungs to the left atrium |
| red blood cell | a blood cell that carries oxygen throughout the body |
| urea | a waste product in the blood that comes from the breakdown of proteins |
| ventricle | either of the two lower chambers of the heart that pumps blood through arteries |
| vein | a blood vessel that carries blood to the heart |
| white blood cells | a blood cell that fights infection by destroying microscopic, disease-causing organisms |
