Respiratory System

3. little ballon-like air sacs where gas exchange takes place
4. the process oxygen and carbon dioxide use to cross the cell membran
7. The bronchi split into many _______________________. They look like tree roots in the lungs.
8. when we ______________, the diaphragm moves up
9. the trachea splits into two _______________
11. the hard stuff that protects the trachea
13. the gas produced by cellular respiration that we exhale
14. when carbon dioxide and oxygen switch places between the blood and the lungs

1. a friendly little flap in our throat that prevents us from choking when we eat food
2. oxygen leaves the lungs to enter the _______________
5. when we ______________, the diaphragm moves down
6. the muscles that we move to breath
10. the gas we need to breath in that is used in cellular respiration
12. Our windpipe, or the main tube of the respiratory system that air enters