1. Gas Exchange
I. Introduction
A. Definition
B. Why?

2. C. Forces & Factors D. Transport 1. What forces drive gas exchange?
Figure 42.22
2. What factors help to maximize exchange?

3. II. Strategies A. Direct 1. Structure 2. Forces
Poriferans, Cnidarians, and Platyhelminthes
Constant water movement
Simple thin structure
Figure 33.4
What would be required to lead this life style?
2. Forces

4. B. Gills
1. Structure
Mollusca to Vertebrata
Figure 42.21

5. Fish Gills

6. 2. Forces a. Passive to b. Active Ram ventilation vs. Gulping
Advantages vs. Disadvantages

7. Circulation of water coupled with perfusion of blood
Figure 42.22

8. swim bladder in bony fishes via the gas gland
Figure 34.15

9. C. Tracheal Systems 1. Insecta a. Structure b. Forces
direct oxygen delivery system to the muscle fibers
Figure 42.23

10. 2. Chordata a. Amphibians i. Structure ii. Forces
Circulate air to lungs from mouth and skin ==PP breathers

11. b. Reptilians
i. Structure
ii. Forces
Circulate air to lungs from mouth ==PP breathers

12. c. Avians i. Structure ii. Forces
Negative pressure breathers move air into their lungs and air sacs
Figure 42.26

13. Negative breathers use muscle contractions to move air
d. Mammalians
i. Air tubes
Negative breathers use muscle contractions to move air
Figure 42.24
pseudostratified ciliated columnar with goblet cells

14. alveoli for gas exchange Type I, Type II cells, and Dust cells
ii. Lungs
alveoli for gas exchange
Type I, Type II cells, and Dust cells
Figure 42.24

15. Lung expansion == muscle contraction
Figure 42.27
Quiet versus Forced Inhalation vs. Exhalation

16. Pons, Medulla Oblongata, and the Hypothalamus
iii. Control
Pons, Medulla Oblongata, and the Hypothalamus
Figure 42.28

17. iv. Transport O2
partial gas pressures
Figure 42.29
Figure 42.30a & b

18. Respiratory pigments transport OXYGEN and also buffer
CO2 is transported via other mechanisms:
Dissolved in plasma about 7%
Bound to globin about 23%
Travels via the bicarbonate shuttle about 70%
iv. Transport CO2