1. GASEOUS EXCHANGE Respiratory surface Respiratory System in Human Control of breathing Gaseous exchange in Insect Gaseous exchange in Fish Gaseous exchange in Plant

2. Respiratory surface Small organisms surface volume ratio is large Larger organism surface volume ratio is small

3. Characteristics of respiratory surface 1. Large surface area 2. Moistened surface 3. Thin and freely permeable to gases 4. With transport system

4. Types

5. Human Respiratory System

6. Lung tissue

7. Mechanism of Breathing Animation

9. Treatment to inhaled air 1. Warmed by capillary in nostrils 2. Moistened by mucus 3. Cleaned and filtered by hair, cilia and mucus

10. Lung capacities Volume of air

11. Control of Breathing Respiratory centre Chemoreceptor pCO 2

12. chemoreceptor 1. Peripheral chemoreceptor Detect both Po 2 and P CO 2 Carotid bodies, aortic bodies 2. Central chemoreceptors Detect P CO 2 Medulla Effect of P CO 2 is larger than Po 2

13. Respiratory centre In medulla oblongata Receive impulse from chemoreceptor Send impulse to diaphragm and intercostal muscle Change rate and depth of breathing

14. Effect to lung pO 2 decrease and pCO 2 increase rate and depth of breathing increase pO 2 increase and pCO 2 decrease Rate and depth of breathing decrease

15. Other effect pCO 2 increase Heart : rate increase Blood vessel: vasodilation Increase rate and volume of CO 2 transport

16. Partial pressure of CO 2 pCO 2 increase Detected by chemorecetor Impulse to respiratory centreImpulse to intercostal and diaphragm muscle by efferent nerve Rate and depth of breathing increase pCO 2 back to normal Feedback

17. Gaseous Exchange in insects Mechanism Abdomen movementAbdomen movement, fluid movement fluid movement Abdomen movementfluid movement

18. Trachea

19. Spiracle

20. During exercise less fluid During exercise During rest more fluid

21. Breathing in fish

22. Gill

23. Gill photo

24. Where is gaseous exchange taking place? Buccal surface Skin Gill in tapole

25. Bird

26. Gaseous Exchange in Plant No special organ for breathing but some special features in various organs for increasing surface area Leave Stem Root

27. Leave

28. Root Hair

29. Lenticel