Overview of gas exchange processes

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
pCO2

12. chemoreceptor
1. Peripheral chemoreceptor
Detect both Po2 and PCO2
Carotid bodies, aortic bodies
2. Central chemoreceptors
Detect PCO2
Medulla
Effect of PCO2 is larger than Po2

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
pO2 decrease and pCO2 increase
rate and depth of breathing increase
pO2 increase and pCO2 decrease
Rate and depth of breathing decrease

15. Other effect
pCO2 increase
Heart : rate increase
Blood vessel: vasodilation
Increase rate and volume of CO2
transport

16. Partial pressure of CO2
pCO2 increase
Detected by chemorecetor
Impulse to respiratory centre
Impulse to intercostal and
diaphragm muscle by efferent nerve
Rate and depth of breathing
increase pCO2 back to normal
Feedback

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

18. Trachea

19. Spiracle

20. During
During rest
exercise less
more fluid
During exercise
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