Respiratory system
Across
- 4. a dome shaped muscle;plays a big role in breathing
- 7. tiny blood containing structures
- 8. a muscular tube that runs behind the windpipe
Down
- 1. the two main organs in which respiration occurs
- 2. an organ that is called the voice box
- 3. a connected system of hollow cavities in the skull
- 5. the windpipe which starts at the larynx
- 6. a set of 12 paired bones which form a protective cage