Across
- 1. sticky fluid
- 5. voice box
- 6. basic unit of nervous system
- 8. carries impulses away from the cell body
- 9. trachea
- 10. fast action without conscious thinking
- 12. lymphatic organs at the back of the throat
Down
- 2. largest lymphatic system
- 3. basic units of respiratory system
- 4. a tiny gap between neuron and dendrite
- 7. prevents the backward flow of blood
- 11. chief breathing organs of humans