Across
- 3. (Lower) The structure of the bronchi that continually gets smaller and branches off.
- 6. (Lower) Tubes which branch at the bottom of the trachea and go to each lung.
- 8. (Upper) Air-filled spaces connected to the nasal passages.
- 10. (Lower) The smallest component of the bronchial tree.
- 11. (Lower) Smooth muscle that regulates breathing in mammals and separates the thoracic cavity and the abdominal cavity.
- 13. (Lower) Windpipe, made of cartilaginous rings that keep the tube open all the time.
Down
- 1. (Upper) Passageway where the nose and mouth meet.
- 2. (Upper) Cells that line the respiratory tract and secrete mucus.
- 4. (Upper) Flap of skin that covers the larynx during swallowing.
- 5. (Lower) The grapelike air sacs at the end of the bronchioles where gas exchange occurs.
- 7. (Lower) Lobed organ that is spongy in nature and fills the thoracic cavity when fully expanded.
- 9. (Upper) Microscopic hairs that line nasal passages to filter out dust and particulates.
- 12. (Upper) The vocal cords are contained here, allowing animals to make sounds.