Respiratory System

4. a thin breathing tube that branches from a bronchus within a lung
8. a mechanism that provides contact between an animals respiratory surface and or water to which it is exposed
9. the transfer of a substance or heat between two fluids flowing in opposite directions
11. one of a pair of breathing tubes that branch from the trachea into the lungs
12. a brain center that directs the activity of organs involved in breathing
14. organ in digestive tract that receives food from the oral cavity
15. sheet of muscle separating the chest cavity from the abdominal cavity

1. one of millions of tiny dead-end sacs within the vertebrate lungs where gas exchange occurs
2. a breathing system in which air is pulled into the lungs
3. a measure of the relative amount of gas in a mixture
5. one of a pair of bands of elastic tissues in the larynx
6. an iron containing protein in red blood cells that reversibly binds o2 and transports it to body tissues
7. the maximum of volume that a mammal can inhale and exhale with each breath
10. the voice box, containing the vocal chords
13. a substance recreated bu alveoli that decreases surface tension in the fluid that coats the alveoli