The document discusses the human respiratory system. It describes how oxygen and carbon dioxide are exchanged in the body through breathing and circulation. The respiratory system includes the nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles and lungs. The nasal cavity contains hairs, mucus-secreting cells and cilia to warm and clean the air. The trachea is supported by C-shaped cartilage and the lungs are protected by the rib cage and diaphragm.

1. DESMOND SO, RD

2. What makes us yawn?

3. What makes us yawn?

4. What makes us yawn?

5. Which part of our
body are in action
when we yawn ?

6. Where does the
exchange of oxygen
and carbon dioxide
take place between
our body and
atmosphere ?

7. In what forms are
oxygen and carbon
dioxide carried
around our body?

8. DESMOND SO, RD

9. In very small organisms:
O2
CO2
• diffuses across cell membrane

10. In larger organisms:
 O2
 CO2
• cannot diffuse across body surface

11. In larger organisms:
1. breathing system (呼吸系統)
- for gas exchange
2. transport system (運送系統)
- for carrying gases to body cells

13. Human breathing system

14. Human breathing system

15. Human breathing system

17. air nasal cavity
pharynx
larynx
trachea

18. air
bronchus
bronchiole
air sac

19. 1 Nostrils and nasal cavity
i) Hairs
•filter larger dust particles

20. 1 Nostrils and nasal cavity
ii) Mucus-secreting cells
traps dust particles & moistens air
mucus

21. 1 Nostrils and nasal cavity
iii) Ciliated epithelial cells
Cilia sweep mucus with dust
particles towards pharynx
cilia

22. 1 Nostrils and nasal cavity
iv) Capillaries
•blood warms up air

23. Self Quiz!
Which of the following structures is/are
found in the nasal cavity?
(1) ciliated epithelium
(2) mucus-secreting cells
(3) hairs
A (1) only
B (1) and (2) only
C (1) and (3) only
D (1), (2) and (3)

24. 2 Pharynx and larynx

25. 2 Pharynx and larynx
pharynx
larynx oesophagus
trachea

26. 2 Pharynx and larynx
food
larynx oesophagus

27. 2 Pharynx and larynx
1 Tongue pushes food
towards pharynx
larynx oesophagus

28. 2 Pharynx and larynx
2 Soft palate moves
up, preventing food
from entering nasal
cavity
larynx oesophagus

29. 2 Pharynx and larynx
3 Larynx rises and
epiglottis covers
entrance to
trachea, preventing
choking
larynx oesophagus

30. 2 Pharynx and larynx
epiglottis
larynx
• made up of
cartilage

31. 2 Pharynx and larynx
vocal cords (聲帶)
• can vibrate to
produce sound

32. 2 Pharynx and larynx

33. 3 Trachea, bronchi and bronchioles
trachea
bronchus
bronchioles

34. 3 Trachea, bronchi and bronchioles
trachea
bronchus
bronchioles

35. 3 Trachea, bronchi and bronchioles
lumen
C-shaped cartilage
• prevents
collapse
ciliated epithelial
cell

36. 3 Trachea, bronchi and bronchioles
Trachea Bronchi Bronchioles
Ciliated Yes Yes Yes
epithelial
cells
Mucus- Yes Yes Absent in
secreting smaller
cells bronchioles
Capillaries Yes Yes Yes
Cartilage C-shaped Circular Absent

37. Self Quiz!
The trachea is supported by many C-
shaped cartilages. These cartilages
A trap dust particles and bacteria.
B warm up the inhaled air.
C vibrate and produce sound.
D keep the trachea open for breathing.

38. Self Quiz!
Mucus in the respiratory tract helps
(1) warm up the air.
(2) moisten the air.
(3) trap the dust particles in the air.
A (1) and (2) only
B (1) and (3) only
C (2) and (3) only
D (1), (2) and (3)

39. 4 Air sacs
•large respiratory surface
air sac
capillary

40. 5 Lungs
•composed of bronchioles and air sacs
•in thoracic cavity (胸腔)

41. 5 Lungs
•protected by rib cage (肋骨籃)
vertebral
column (脊柱)
ribs
sternum
cartilage (胸骨)

42. 5 Lungs
intercostal
diaphragm muscles
• sheet of
muscle

43. 5 Lungs

44. 5 Lungs
rib
intercostal muscle
outer pleural membrane
right
inner pleural membrane
lung
pleural cavity

45. 5 Lungs
•pleural cavity filled with
pleural fluid (胸腺液)
as lubricant
(潤滑劑) right
lung
pleural cavity

46. Misconceptions !!
Hairs are present inside
the nasal cavity to filter
air

47. Misconceptions !!
Hairs are present at the
nostrils of the nose to
filter the incoming air

48. Misconceptions !!
Dust particles are
trapped by cilia inside
the nasal cavity

49. Misconceptions !!
Dust particles are trapped by
mucus. The trapped dust
particles are swept by the beating
action of cilia to the pharynx
where they are swallowed or
coughed out

50. Self Quiz!
The human breathing system
consists of the respiratory tract
and structures that aid breathing.

51. Self Quiz!
Air flow along respiratory tract:
nostrils nasal cavity
pharynx larynx
trachea bronchi
bronchioles air sacs

52. Self Quiz!
In the nostrils, hairs filter
larger dust particles.

53. Self Quiz!
In the lining of nasal
cavity, trachea, bronchi and
mucus-secreting cells
bronchioles, mucus-secreting
cells
mucus secrete mucus to
moisten the air.

54. Self Quiz!
In the lining of nasal cavity,
trachea, bronchi and bronchioles,
mucus
mucus traps the dust particles
and bacteria.

55. Self Quiz!
In the lining of nasal cavity,
trachea, bronchi and bronchioles,
blood in the capillaries
blood
warms the incoming air.