organ systems

3. living structure that makes up the skeleton and supports and protects the body.
8. smooth, flexible tissue found at joints that reduces friction and prevents bones from rubbing together.
10. pair of muscles that work against each other — when one contracts, the other relaxes.
11. air sac in the lungs where oxygen enters the blood and carbon dioxide leaves it.
13. amount of space something takes up (in breathing, it refers to how much air is in the lungs).
14. chemical process in cells that releases energy from glucose using oxygen.
17. organ in the chest that takes in oxygen and removes carbon dioxide.
19. group of similar cells working together to perform a function.
20. group of different tissues working together to perform a specific function.
21. set of ribs that protects the heart and lungs.
23. strong cord of tissue that connects muscle to bone.

1. of many cells (like humans, animals, and plants).
2. breathe out air from the lungs.
4. system group of organs working together to carry out a major body function (e.g., the respiratory system).
5. breathe in air into the lungs.
6. strong, stretchy band of tissue that connects bone to bone.
7. a muscle shortens and tightens to produce movement.
9. dome‑shaped muscle under the lungs that helps with breathing by moving up and down.
12. place where two bones meet, allowing movement.
15. the bones in the body that provide support, protection, and movement.
16. a tube that carries air from the mouth/nose to the lungs.
18. system body system that brings oxygen into the body and removes carbon dioxide.
22. marrow soft tissue inside bones where blood cells are made.