1. Anatomy and Physiology

2. Organisation of the airway Pharynx Right primary bronchus Nose Nasal cavity Oral cavity Larynx Trachea Lungs

3. Terminal airway Terminal bronchiole Alveolar duct Respiratory bronchioles Smooth muscle Alveoli

4. Perfusion of the alveoli Capillaries Terminal bronchiole Branch of pulmonary artery Alveolus Branch of pulmonary vein Respiratory bronchiole

5. Alveolar design Walls are very thin Large surface area Fluid lined Highly perfused

6. Alveolar design Aqueous layer Aqueous macrophage Lamella body (stores surfactant) Type ll pneumocyte-lining cell (produces surfactant) Type l Lining cell Capillary CO 2 O2O2

7. Lung development Embryonic (4-7 weeks) Pseudoglandular (5-17 weeks) Canalicular (16-26 weeks) Alveolar period (36 weeks) – post natal years Saccular period (24-38 weeks)

8. Canicular period Diameter of airway increases Primitive alveolus is formed Type I and Type II cells differentiate Surfactant production begins

9. Lung volumes Dead space RV ERV TV IRV Maximal inspiratory level Resting expiratory level Maximal expiratory level RV ERV TV IRV FRC IRV = Inspiratory reserve volume ERV = Expiratory reserve volume TV = Tidal volume RV = Residual volume

10. Lungs and heart Oxygenated blood Deoxygenated blood Lungs Pulmonary veins (oxygenated blood) Pulmonary artery (deoxygenated blood) Pulmonary capillaries Right side of heart Left side of heart Systemic arterial system Systemic capillaries

11. Foetal circulation Oxygenated blood Deoxygenated blood Lungs Pulmonary capillaries Ductus arteriosus Foramen ovale Pulmonary veins (oxygenated blood) Pulmonary artery (oxygenated blood) Right side of heart Left side of heart Ductus venosus Inferior vena cava Liver Portal vein Aorta Descending aorta Blood returning from systemic venous system Umbilical vein Umbilical arteries Deoxygenated blood Placenta

12. Changes after birth Air into lungs Rise of oxygen level in alveoli Lungs become perfused Pressure between right and left atrium falls Foramen ovale closes

13. Ductus arteriosus Placental prostaglandin E 2 removed Vasoconstrictors increase Duct closes (functional – 12 hours) Remodelling – several weeks

14. Diaphragm Lungs Pleural space Taking a breath

15. Air liquid SURFACE Polar H 2 O molecules attract Surface tension

16. where: P = pressure ST = surface tension r = radius of the bubble P = 2ST/r Laplaces law

17. SalineAir Von Neergaard

18. P = 2x1= 0.2 10 P = 2x1= 0.4 5 10 5 Connected bubbles

19. Alveoli as bubbles

20. Phospholipids Polar heads Insoluble tails Negative tails Monolayer Hypophase Alveolar gas Surfactant action

21. Surfactant packing Reduce surface tension Resist collapse

22. Properties of surfactant Rapid adsorption Efficient spreading Lower surface tension

23. 1 2 34 5 6 7 DPPC - dipalmitoylphosphatidylcholine 50%* Reduces alveolar surface tension PG - phosphatidylglycerol 7%* Promotes the spreading of surfactant throughout the lungs Apoproteins or surfactant specific proteins 2%* 1. Serum proteins 8%* 2. Other lipids 5%* 3. Other phospholipids 3%* 4. Phosphatidylinositol 2%* 5. Sphingomyelin 2%* 6. Phosphatidylethanolamine 4%* 7. Unsaturated Phosphatidylcholine 17%* * By molecular weight Composition

24. Water soluble Insoluble fatty acid chains DPPC Dipalmitoyl phosphatidylcholine

25. Surfactant proteins SP-A Host defence, tubular myelin SP-D Immune activity SP-B and SP-C Spreading and adsorption

26. Production and release Type ll cell Alveolar air space Hypophase Type I cell Basal lamina Capillary endothelium Monolayer Hypophase Alveolar gas LMVB Golgi RER DMVB Type I cell Tubular myelin Lamellar bodies

27. Stimulus for release Gas entering lungs Alveolar stretch (inspiration) Adrenergic innervation Prostaglandins

28. TYPE II CELL Loss from lungs Choline fatty acids Lysosomes MVB Degradation Endoplasmic reticulum Golgi Synthesis and secretion Lamellar bodies Recycling Precursors Reuptake Catabolic Anabolic Alveolar transformations ALVEOLUS Other losses - Macrophages - Airways - Other lung cells Surfactant cycle

29. Tubular myelin Structure of crossing bilayers Need SP-B, SP-A and Ca 2+ Facilitates adsorption