1. Gas Exchange From Ch. 42 08 April 20151Gas-Exchange.ppt

2. 08 April 2015Gas-Exchange.ppt2 Animal Life Four critical processes Obtain energy and material Ingest, digest, absorb Obtain oxygen Dispose of nitrogenous waste NH 3, urea, uric acid Dispose of CO 2

3. Animal Life Multicellular organisms Internal circulation Coordination, information transfer Structural maintenance Movement Maintenance of homeostatic internal environment 08 April 2015Gas-Exchange.ppt3

4. 08 April 2015 Gas-Exchange.ppt4 Gas Exchange Exchange of O 2 for CO 2 occurs by diffusion Structure of gas exchange organs facilitates diffusion

5. 08 April 2015 Gas-Exchange.ppt 5 Gas Exchange T o, temperature S, solubility mol. wt., molecular weight of diffusing gas r, rate of diffusion  P, difference in partial pressure (O 2 or CO 2 ) A, area of exchange membrane d, distance

6. Gas Exchange Systems Gills in aquatic & marine animals  Large area  Hemoglobin & other oxygen transporters  pO 2 variable in water 08 April 2015Gas-Exchange.ppt6

7. Gas Exchange Systems 08 April 2015Gas-Exchange.ppt7 Fish gill Filaments with large area Countercurrent flow maintains ΔP

8. Gas Exchange Systems 08 April 2015Gas-Exchange.ppt8 Fish gill  Countercurrent flow maintains ΔP

9. Gas Exchange Systems 08 April 2015Gas-Exchange.ppt9 Tracheal systems of arthropods large area Ventilation (?) to maintain ΔP

10. Gas Exchange Systems 08 April 2015Gas-Exchange.ppt10 Lungs in mammals Diaphragm & other muscles for ventilation

11. Gas Exchange Systems 08 April 2015Gas-Exchange.ppt11 Lungs in mammals Enclosed, protected by ribs

12. Gas Exchange Systems Lungs Thin, delicate membrane between air and blood 08 April 2015Gas-Exchange.ppt12

13. 08 April 2015 Gas-Exchange.ppt 13 Gas Exchange T o, temperature S, solubility mol. wt., molecular weight of diffusing gas r, rate of diffusion  P, difference in partial pressure (O 2 or CO 2 ) A, area of exchange membrane d, distance

14. 08 April 2015 Gas-Exchange.ppt 14 Gas Exchange Constants o temperature (= body temperature) o solubility (property of O 2 or CO 2 ) o molecular weight (property of O 2 or CO 2 ) These don’t change. Disregard.

15. 08 April 2015 Gas-Exchange.pp t 15 Gas Exchange r, rate of diffusion  P, difference in partial pressure (O 2 or CO 2 ) A, area of exchange membrane d, distance

16. 08 April 2015 Gas-Exchange.ppt 16 Gas Exchange To maximize diffusion rate: Maximize  P Maximize Area Minimize distance. These result from evolutionary and physiological adaptation.

17. 08 April 2015 Gas-Exchange.ppt 17 Gas Transport Ventilation of alveoli O 2 diffusion from alveoli to hemoglobin in RBC’s Equilibrium pO 2 = 100 mmHg Diffusion from hemoglobin to body tissues Equilibrium pO 2 = 40 mmHg

18. 08 April 2015 Gas-Exchange.ppt 18 Gas Transport CO 2 diffusion from body tissues to hemoglobin Equilibrium pCO 2 = 45 mmHg Diffusion from hemoglobin in RBC’s to alveoli Equilibrium pCO 2 = 40 mmHg Ventilation of alveoli

19. 08 April 2015 Gas-Exchange.ppt 19 Gas Transport Hemoglobin Oxygen-hemoglobin dissociation curve Hb binds O 2 at high pO 2 Hb releases O 2 at low pO 2

20. 08 April 2015 Gas-Exchange.ppt 20 Gas Transport Hemoglobin Oxygen-hemoglobin dissociation curve Exercise lowers pO 2 and pH in muscles, higher temperature Hb releases more O 2 at low pO 2, low pH, and high temperature