Circulatory System Vocabulary

1.   artery – a blood vessel that carries blood away from the heart to other parts of the body.

2.   vein – a blood vessel that carries blood back to the heart from another part of the body.

3.   capillary – a blood vessel with very thin walls that allow oxygen and carbon dioxide to pass through (capillaries connect arteries and veins)

4.   atrium – either of the upper chambers of the heart.

5.   ventricle – either of the lower chambers of the heart

6.   platelets – the parts of blood that can stick together to help blood clot

7.   red blood cells – carry oxygen from the lungs throughout your body and carry carbon dioxide back to the lungs so you can breathe it out

8.   white blood cells – help your body fight infections when you become ill

9.   plasma – the watery liquid part of your blood

10.  valve – an opening that allows blood to flow in one direction but stops it from flowing in the other direction