Unit 2A Human Form & Function

1. Unit 2AHuman Form & Function Body systems The respiratory system

2. Further information • Further information about this topic can be found in Our Human Species(3rd edtn)Chapter 11, sections 1-2, 4-6

3. Background reading • Our Human Species (3rd edtn.) Chapter 11, Gas Exchange Sections 1, 2, 4, 5, 6, 7 Student work book Topic 9, Respiratory system

4. The respiratory system Structure

5. Organs of the respiratory system Larynx Trachea Rib cage Bronchus Mediastinum Lung Diaphragm

6. Section through the head Nasal cavity Palate Teeth Tongue Pharynx Epiglottis Hyoid bone Vocal cords Larynx Esophagus The Miles Kelly Art library, Wellcome Images

7. The mucous lining • The nasal cavity and upper airways have amucous lining. • The epithelial lining containsgoblet cellswhich secrete a clear, stickymucus. • The function of mucus is to trap dirt particles and microbes before they enter the lungs.

8. The nose (nasal cavity) • Air enters and leaves the body through the nose. • Here it is cleaned, warmed and moistened before entering the body. • The nasal secretions contain an anti-bacterial enzyme –lysozyme.

9. A section through the nasal cavity Sinus NASAL CAVITY Hard palate Soft palate Nostril The Miles Kelly Art library, Wellcome Images

10. The larynx (Adam’s apple or voice box) • The larynx is a box-like structure constructed from nine cartilages and is the entrance to the trachea and lungs. • The larynx houses the vocal folds orvocal cords. • The entrance to the larynx is protected by theepiglottis. Gray’s Anatomy

11. The bronchial tree Larynx Trachea Bronchus Bronchiole The Sourcebook of Medical Illustration (The Parthenon Publishing Group, P. Cull, ed., 1989)

12. Trachea & bronchi • The trachea & bronchi are reinforced with C-shaped rings of cartilage (these prevent the tubes collapsing during inhalation).

13. The bronchi Cartilage rings Muscular wall Mucous lining The Miles Kelly Art library, Wellcome Images

14. The upper airways are lined with a ciliated mucous membrane • The sticky mucus traps dirt & microbes • The cilia sweep the dirty mucus up the trachea and into the throat.

15. The ciliated lining tissue Mucus-secreting goblet cells Cilia • G. Meyer, ANHB-UWA,

16. EM of ciliated epithelium & goblet cells D Gregory & D Marshall, Wellcome Images

17. Alveoli • The brochioles terminate in microscopic clusters of air sacs – thealveoli. • Gas exchange takes place in the alveoli. Alveoli • G. Meyer, ANHB-UWA

18. The alveoli (air sacs) The Miles Kelly Art library, Wellcome Images

19. Section through a lung showing alveoli and blood supply M I Walker, Wellcome Images

20. The respiratory system Gasexchange

21. Exchange surfaces • Like all exchange surfaces, the alveoli: • are very thin • have a large surface area • are moist • have a rich blood supply

22. Breathing • Breathing (sometimes referred to asventilation) is the process of moving air into and out of the lungs. • The purpose of breathing is to exchangeoxygenandcarbon dioxidebetween the lungs and the air .

23. Boyle's law • Boyle's law states that: for a fixed amount of gas kept at a fixed temperature, pressure (P) and volume (V) are inversely proportional (while one increases, the other decreases). • This can be stated mathematically as:PV = k • where: P is thepressure, V is thevolume&k is a constant value representative of the pressure and volume of the system.

24. Respiration • Respiration is the transport of oxygen from the air to the tissues and the transport of carbon dioxide in the opposite direction.[not to be confused with the process of cellular respiration discussed earlier]

25. External respiration and Internal respiration • External respirationis the movement of O2 and CO2 between the lungs and the bloodstream. • Internal respirationis the exchange of O2 and CO2 between the blood and the tissues.

26. External respiration Breathing maintains the correct concentration of gases in the lungs Concentration gradient

27. Breathing – inhaling(remember P1V1 = P2V2) V = volume of thoracic cavity P1 = pressure in thoracic cavity P2 = air pressure

28. Thoracic volume Rib cage relaxes Diaphragm domed Rib cage raised Diaphragm flattens

29. A bicycle pump works in much the same way as the lungs P1V1 = P2V2

30. If you increase the volume of the chamber air is sucked in The lungs work in much the same way as a bicycle pump If you decrease the volume of the chamber air is forced out

31. Breathing – exhaling(remember P1V1 = P2V2) V = volume of thoracic cavity P1 = pressure in thoracic cavity P2 = air pressure

32. INHALE EXHALE Thoracic volume decreasedThoracic pressure > air pressure Thoracic volume increasedThoracic pressure < air pressure Ribcage raised Ribcage lowered Diaphragm flattened Diaphragm domed The Miles Kelly Art library, Wellcome Images

33. Why breathe? Fresh air passing through the lungs delivers oxygen to the red blood cells. At the same time, waste carbon dioxide is removed from the blood. This can only occur if fresh air is constantly circulating through the lungs. Carbon dioxide Oxygen Wellcome Photo Library

34. Oxygen transport • Oxygen combines withhaemoglobinin RBCs to formoxyhaemoglobin.

35. Carbon dioxide transport - • Most CO2 is transported in the plasma as dissolvedbicarbonate ions.

36. Oxygen saturation

37. Diseased lung tissue B A CDC C Photo by Pöllö • healthy lung tissue • Smoker’s lung • Emphysema

38. Study Guide Read: • Our Human Species Chapter 11, sections 1-2, 4-6 Complete: • Workbook Topic 9, Respiratory system