U3 Study Guide

3. microorganisms that are not made of cells, so they need to enter the host's cells to reproduce.
4. smallest blood vessels, where exchange happens.
10. organ that pumps blood through the body.
11. dome-shaped muscle under the lungs that helps us breathe.
13. long tube in our throat that connects the nose to the lungs.
14. cells in blood that fight diseases.
16. tubes that carry oxygen-poor blood back to the heart.
17. gas that we inhale to live.
19. system in the human body that has as a function to transport blood, nutrients and oxygen. to all human's tissues.

1. mechanism of breathing which living being breathe out carbon dioxide.
2. pair of organs that expands when breathing in and contracting when breathing out.
5. cells in blood in charge of the clotting process.
6. mechanism of breathing which living beings breathe in oxygen.
7. system in the human body in charge of breathing in oxygen and breathing out waste gasses.
8. also known as germs or pathogens, which can be harmful or beneficial to human beings.
9. tubes that carry blood away from the heart to the body.
12. tubes that connect the lungs to the trachea.
15. small branches that at each's end, alveoli can be found.
18. little air-sacs surrounded by capillaries where the gas exchange process takes place.