The document discusses various aspects of respiration including external respiration in the lungs involving gas exchange, and internal respiration in the mitochondria involving oxygen utilization. It describes the conducting and respiratory zones of the lungs, pleura, pulmonary pressures, respiratory muscles, mechanisms of inspiration and expiration. It also summarizes lung compliance, surfactant, pulmonary ventilation tests, lung volumes, dead space, and pulmonary function tests.

2. RESPIRATION External respiration (Lungs): Pulmonary ventilation Gas exchange (lungs # blood # tissues) Gas transport Internal respiration (Mitochondria): - O2 utilization.

3. Non respiratory functions of the lungs Acid base balance ACE (Activation : ATI ATII). Airway protection Vapor loss VR help Vocalization

4. Conducting & Respiratory Zones

5. Pneumocytes Types

6. Visceral & parietal pleura

7. Boyle’s Law

8. Pulmonary Pressures Diaphragm

9. Pulmonary Pressures

11. Importance of Negative IPP Lung expansion Venous & lymph return IPP become +ve in: - Pneumothorax - Valsalva manouver

12. Pneumothorax

13. Respiratory Muscles Abdominal ms

14. Mechanism of Inspiration

15. Mechanism of Respiration Pause Recoil Distention Lungs +++ _ _ _ IAP Rushes out Rushes in Air Less - ve More - ve IPP _ _ _ +++ Thorax Passive Active Process Expiration Inspiration

16. Surfactant Lipoprotein (phospholipid, apoproteins & Ca++). produced by alveolar type II cells. ST so prevents: - collapse of small alveoli in expiration. - pulmonary edema.

17. Surfactant deficiency RDS 100 % O2 inhalation. Occlusion of pulmonary artery or major bronchus. Smoking. Hyperinsulinism e.g baby of diabetic mother. Myxedema (hypothyroidism). Hypocorticism

18. Physical Properties of the Lungs Elasticity. Surface tension. Compliance (Distensibility). 

19. Lung Compliance Definition change in lung volume/change in distending pressure: C=  V/  P ml/cm H2O Types : # Static C ( lungs only, 200). # Dynamic C (lungs + thoracic wall, 110)

20. Static Lung Compliance 200 ml / cmH2O Hysteresis loop Surfactant conc. during deflation Inflation Deflation

21. Static Lung Compliance

22. Lung Compliance obesity Poliomyelitis RDS Edema Emphysema Congestion Atheletes Lung fibrosis Aging - - - - - - - - - - - - - - ++++++++

23. Breath Work During inspiration or forced expiration. 3 parts: 1- Elastic work (or compliance). 2- Air resistance work (medium bronchi). 3- Tissue resistance work (viscosity). Air way resistance 1/a diameter of bronchi. Breath work increases in : Surfactant Compliance & Airway resistance.

24. Factors affecting bronchi diameters Histamine,adenosine VIP Chemicals Cold Warm Temp. Max. at 6 AM Max. at 6 PM Circadian rhythm Expiration Inspiration (Lung expansion) Respiration - - - - - - - - - - - - - ++++++++++ PCO2 Parasymp. (Muscarinic R) Symp. (B2 receptors). ANS Bronchoconstriction Bronchodilation Factors

25. Pulmonary Ventilation it is the air exchange (atmosphere & alveoli). Normally: air vol. in insp. = air vol. in exp. Spirometer measures lung volumes & capacities. High volumes in tall people, high altitude low volumes in female, pregnancy, short & smokers

27. The amount of air remaining in the lungs at the end of a maximum expiration. 1200 ml (30% TLC) during rest ( in exercise). in aging & obstructive lung diseases. Measured by Helium dilution method ( NOT spirometer). Residual Volume

28. Helium Dilution Method RV = FRC – ERV TLC= FRC + IC

29. Continuous gas exchange in between breathes. Prevent alveolar collapse. D of asthma & emphysema ( 70%). Medicolegal importance: lost in pneumothorax but minimal air w is sufficient for floatation of lung in water & absent in stillbirth. RV Significance

30. Vital Capacity Max. vol. of air can be expired after max. inspiration. Measured by spirometer. 4600 ml ( 2 - 2.5 L/m2). Index of pulmonary function & physical fitness.

31. Factors Affecting VC Chest/ lung diseases ______ Pathological Recumbency Standing Pregnancy Athelets Females Males Physiological - - - - - - - - - - +++++++++

32. Dead Space The part of res. system with no gas exchange. TYPES: Anatomical DS Alveolar DS Physiological DS :Anatomical + Alveolar DS Normally: Physiological = Anatomical DS Lung diseases: Physiological > Anatomical DS

33. DS Importance Warms,filters & moistens inspired air. Causes difference in composition between expired air & alveolar air (more CO2 & less O2). Shallow rapid breath hypoxic hypoxia.

34. DS Measurement Anatomical DS : Fowler method (single breath N2 test). Physiological DS:Bohr equation. 150 – 167 ml. ANS can +++ or - - - - DS

35. Pulmonary Ventilation Tests Pulmonary ventilation ( minute respiratory volume): RR X TV Alveolar ventilation: RR X (TV – DS)

36. Pulmonary Function Tests Pulmonary function tests Static lung volumes Dynamic lung volumes

37. Dynamic lung volumes Volume/unite time Maximum breathing capacity Breathing reserve Timed vital capacity Maximum flow rate

38. Maximum breathing capacity (Maximum ventilatory volume) Max. vol. of air inspired/expired using the deepest & fastest respiratory effort /min. Males: 80-180 L /min Females: 60-120 L /min Spirometer is used for 15 sec. to avoid fatigue & resp. alkalosis. Then X 4. Better index for physical fitness than VC.

39. Breathing Reserve BR = MBC - MV BR/MBC > 90 %. Dyspnic index : BR/MBC < 70 %. Max. velocity of expired air. 10 L/m (by peak flowmeter). --- in obstructive lung diseases . Maximum flow rate

40. Timed vital capacity (Forced expiratory volume) % vol. of expired air at end of 1 st sec. FEV1 (FEV/FVC) = 80 %. Measured by spirometer. Differentiates between restrictive & obstructive lung diseases.

41. FVC > 80 % Normal < 80 % FEV1/FVC ratio > 80 % Restrictive < 80 % Obstructive

42. Spirometer Tests Normal:70 % Small air ways obstruction <70 % FVC > 80 % Normal < 80 % FEV1/FVC ratio > 80 % Restrictive < 80 % Obstructive Forced expiratory flow FEF 25% FEF 50% FEF 75%

43. Is the Obstruction Fixed or Reversible? In some obstructive airways diseases, a part or all of the obstruction will be reversible with bronchodilators . Therefore in all cases where the technician notes obstruction, two inhalations of a bronchodilator will be given to the subject . An improvement of 12% in the FEV 1 or FVC is considered a significant response with an increase of at least 200ml . Asthma is considered the prototypical disease reactive to bronchodilators . However, more &quot; fixed &quot; types of obstruction such as emphysema and chronic bronchitis may also show reversibility . In addition, because asthma is a variable disease, at times pulmonary function tests may appear entirely normal . One will therefore make the diagnosis by clinical history or attempt to provoke obstruction using a &quot; bronchoprovocational &quot; agent such as methacholine or cold air which can illicit bronchoconstriction which might not otherwise be seen .