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Trachea (Generation #1) Primary Bronchi (Generation #2) Conducting Airways Generations 1-16 2 o Bronchi (Generation #3) Respiratory Zone Generations ~17-23.

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Presentation on theme: "Trachea (Generation #1) Primary Bronchi (Generation #2) Conducting Airways Generations 1-16 2 o Bronchi (Generation #3) Respiratory Zone Generations ~17-23."— Presentation transcript:

1 Trachea (Generation #1) Primary Bronchi (Generation #2) Conducting Airways Generations o Bronchi (Generation #3) Respiratory Zone Generations ~17-23 Alveoli Respiratory Bronchioles

2 PAPA PaPa PvPv Zone 1 P A >P a >P v Low Flow PAPA PaPa PvPv PAPA PaPa PvPv Zone 2 P a >P A >P v Waterfall Zone 3 P a >P v >P A Hi Flow O2O2 CO 2 venousarterial P B =0 P A <0 Flow= P/R

3 O2O2 CO 2 venousarterial P B =0 P A <0 O2O2 CO 2 venousarterial P B =0 P A >0 Atmospheric Air High O 2 (150 mmHg) CO 2 ~ 0 Alveolar Air O 2 ~100 mmHg CO 2 ~ 40 mmHg InspirationExpiration

4 Ficks law J = DA ( C/ X) Lung Chest Wall Stuck Together Lung Air leak Pneumothorax Lung collapses & Chest expands

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6 VTVT Total Lung Capacity Expiratory Reserve Inspiratory Reserve FRC Inspiratory Capacity Residual Volume Vital Capacity

7 Expiratory Reserve Residual Volume Vital Capacity VTVT Total Lung Capacity Inspiratory Reserve FRC Inspiratory Capacity TLC RV IC VTVT IR FRC ER VC

8 VLVL V1V1 VLVL V1V1 C 1 V 1 =NC 2 (V 1 +V L ) =N V L =(C 1 /C 2 )V 1 –V 1 Equilibrate Concentration C 1 V 1 = C 2 (V 1 +V L )

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11 Expiratory Reserve Residual Volume Vital Capacity VTVT Total Lung Capacity Inspiratory Reserve FRC Inspiratory Capacity 600 ml 2.5 L 1.2 L 5 L ~6.5 L

12 Lung Chest Wall Stuck Together Lung As we remove air from pleural space the lung expands & the chest wall gets pulled in.

13 Chest Wall Recoil Force Lung Wall Recoil Force P pl = 0 P pl = -2 Normal Emphysema lung recoil Fibrosis lung recoil Pneumo- thorax P pl = -8 Balance of Forces Determines FRC Hookes Law: F = -kx Intrapleural space Increasing volume Decreasing volume Normal FRC P pl = -5

14 P1P1 P2P2 For same T, P 1 >P 2 (I.e. 2T/r 1 > 2T/r 2 ) LaPlace 2T=Pr P=2T/r

15 Surface Area (relative) Surface Tension (dynes/cm) WaterDetergent Lung Surfactant Plasma 80 Surface Area Surface Tension Surfactant 40% Dipalmitoyl Lecithin 25% Unsaturated Lecithins 8% Cholesterol 27% Apoproteins, other phospholipids, glycerides, fatty acids

16 Surface Area (relative) Surface Tension (dynes/cm) WaterDetergent Lung Surfactant 80 Surface Area Surface Tension 1.Reduces Work of Breathing 2.Increases Alveolar Stability (different sizes coexist) 3.Keeps Alveoli Dry

17 Static Compliance Curves Expiration Inspiration

18 Static Compliance Curves

19 Chest Wall Recoil Force Lung Wall Recoil Force Normal FRC P pl = -5 Normal Balance of Forces Determines FRC Hookes Law: F = -kx Intrapleural space Increasing volume Decreasing volume P pl = 0 P pl = -2 Emphysema lung recoil Fibrosis lung recoil Pneumo- thorax P pl = -8

20 Lung has weight -8 P pl = Apex Base Chest Wall

21 Regional- Apex to Base Differences

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23 Apex to Base Differences

24 P A (cm H 2 O) Air Flow (L/s) time (sec) P pl ( cm H 2 O ) The linear Dashed trace is the P pl required to overcome recoil forces. More P pl (solid curve) is required to overcome airway resistance to flow. N.B. P = P A -P B ResistFlow. V T (L) Respiratory Cycle InspirationExpiration Rest FRC Inspiration End Inspiration Air Flow P A = 0 P pl End Expi- ration-FRC Expiration time Respiratory Cycle Single V T Breath P B =0

25 Static Compliance Curves Expiration Inspiration

26 P A (cm H 2 O) Air Flow (L/s) time (sec) P pl ( cm H 2 O ) Case of ZERO Resistance V T (L) Respiratory Cycle InspirationExpiration Rest FRC Inspiration End Inspiration Air Flow P A = 0 P pl End Expi- ration-FRC Expiration time Respiratory Cycle Single V T Breath P B =0

27 P A (cm H 2 O) Air Flow (L/s) time (sec) P pl ( cm H 2 O ) The linear Dashed trace is the P pl required to overcome recoil forces. More P pl (solid curve) is required to overcome airway resistance to flow. N.B. P = P A -P B ResistFlow. V T (L) Respiratory Cycle InspirationExpiration Rest FRC Inspiration End Inspiration Air Flow P A = 0 P pl End Expi- ration-FRC Expiration time Respiratory Cycle Single V T Breath P B =0

28 P A (cm H 2 O) Air Flow (L/s) time (sec) P pl ( cm H 2 O ) V T (L) Respiratory Cycle InspirationExpiration Rest FRC Inspiration End Inspiration Air Flow P A = 0 P pl End Expi- ration-FRC Expiration time Respiratory Cycle Single V T Breath P B =0 Case of HIGH Resistance

29 Mild Expiratory Effort (P+13) 0 Normal at FRC -5 0 Dynamic Compression of Airways P TP =+5 P Pl - P A = -5

30 Strong Expiratory Effort (P+30) EPP Normal EPP Emphysema in unsupported airways EPP Emphysema +11 P Pl -P A = Dynamic Compression of Airways EPP Equal Pressure Point (in supported airways) +13 Mild Expiratory Effort (P+13) Normal at FRC P TP =+5 P Pl - P A = -5 Low V L & Basal Alv also like this

31 Airway Generation Total Cross Sectional Area Conducting Zone Resp Zone v = Flow/A N R = Dv/ =density D= diameter v= velocity = viscosity Airway Generation Resistance Subsegmental Bronchi Resistance 8 l R= r 4 knumber R= A 2

32 Lung Volume Airway Resistance Normal Recoil Emphysema Fibrosis

33 Normal Resistance Obstructive Recoil Restrictive time (sec) Volume FRC Inspiration

34 Forced Vital Capacity TLC FEV 1.0 FVC 1 sec FEV 1.0 = 4 L FVC = 5 L % = 80% RV Normal TLC FEV 1.0 FVC 1 sec FEV 1.0 = 1.2 L FVC = 3.0 L % = 40% RV Obstructive airway resist Restrictive lung recoil TLC FEV 1.0 FVC 1 sec FEV 1.0 = 2.7 L FVC = 3.0 L % = 90% RV

35 Effort Independent limb in forced expiration. TLC RV Expiratory Flow Lung Volume Flow-Volume Curves Due to Dynamic Airway Compression and airway collapse.

36 Inverted Inspiration RV Expiratory Flow Forced expiration Inspiration Inspiratory Flow TLC Lung Volume

37 Normal Obstructive Restrictive Lung Volume (L) Flow Rate (L/sec) 9

38 TLCRV Lung Volume (L) Alveolar Plateau Dead Space Washout 4. N 2 Concentration (%) Critical Closing Volume Test Closing Volume

39 Apex to Base Differences

40 TLCRV Lung Volume (L) Alveolar Plateau Dead Space Washout 4. N 2 Concentration (%) Critical Closing Volume Test Closing Volume Increased Closing Volume

41 P O2 =100 mm Hg 21 ml O 2 /dL P O2 =100 mm Hg 0.3 ml O 2 /dL O2O2 O2O2 P O2 =100 mm Hg 21 ml O 2 /dL P O2 =100 mm Hg 0.3 ml O 2 /dL dissolved 20 ml O 2 /dL HB-O 2 O2O2 O2O2

42 Expired Lung Volume (L) Alveolar Plateau Inspired O 2 diluted by alveolar N 2 N 2 Concentration (%) A B Fowlers Test Area A = Area B VdVd

43 The Bohr Equation V D1 (P ACO2 – P ECO2 ) = V T P ACO2 V D2 (P aCO2 – P ECO2 ) = V T P aCO2 D. Sample Calculation V T = 600 ml P ACO2 = 38 mmHg P ECO2 = 28 mmHg P aCO2 = 40 mmHg V D1 = 600(38 – 28)/38 = 158 ml V D2 = 600(40 – 28)/40 = 180 ml E.Alveolar Ventilation... V E = V D + V A = V T frequency... V A = V E - V D. 1.For V T = 500 ml, f = 10/min, V D = 150 ml, what is V A ?. V A = = 3500 ml/min.. 2.If V E is doubled by increasing V T what is V A ? = 10, = 8500 ml/min.. 3.If the same V E is obtained by doubling frequency, what is V A ? = 10, = 7000 ml/min. Thus increasing V T rather than frequency is more effective for V E.

44 F. Alveolar Ventilation and CO 2 production. V CO2 = Expired CO 2 - Inspired CO 2. =V A F ACO2. V A x P ACO2 = P A..V CO2 K V A = P ACO2

45 XIV.RESPIRATORY GAS CASCADE P O2 P CO2 mm Hgmm Hg Air (dry) Trachea (humidified; ) Alveolus (some O 2 absorbed by blood)10040 Arterial (R-L Shunt)9040+ Mixed venous (O 2 absorbed by tissues)4046

46 time in Capillary (sec) P O2 mm Hg Normal Transit Time Exercise Shortens Transit time Thickened Alveolar Membrane O 2 Diffusion in Pulmonary Capillaries (transit time)

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50 Capillary Wall CO 2 + H 2 O H 2 CO 3 H + + HCO 3 - O2O2 CO 2 Cl - H + + HbO 2 HHb + O 2 Carbamino HHb-CO 2 O2O2 Tissue CO 2 Loading & O 2 Unloading c.a.

51 Alveolar Wall O2O2 CO 2 Cl - H + + HbO 2 HHb + O 2 Carbamino HHb-CO 2 O2O2 Lungs CO 2 Unloading & O 2 Loading c.a. HCO 3 - CO 2 + H 2 O H 2 CO 3 H + + HCO 3 -

52 O 2 helps CO 2 unloading Arterial ( O 2 ) Exercise Venous Rest Venous P CO2 (mm Hg) CO 2 Content (ml CO 2 /100 ml blood) HALDANE SHIFT

53 P O2 = 40 P CO2 = 45 Normal V A /QLow V A /QHigh V A /Q CO 2 = 45 P O2 = 150 P CO2 = 0 P O2 = 100 P CO2 = 40 P O2 = 150 P CO2 = 0... Ventilation Perfusion Ratios No flow

54 P O2 = 40 P CO2 = 45 Low V A /Q. Normal V A /Q. P O2 = 100 P CO2 = 40 High V A /Q. P O2 = 150 P CO2 = 0 P O2 (mm Hg) P CO2 (mm Hg) Base Apex

55 Flow of Blood or Air V A /Q Ratio Bottom Top Distance up Lung Ventilation Perfusion V A /Q

56 Mechanisms of Hypoxemia P aO2 P aCO2 P O2 (A-a)P aO2 with 100% O 2 HypoventilationlowHighNorm>550 Diffusionlownorm-lowhigh>550 R-L Shuntlownorm-lowhigh 550 Other Hypoxemias (without low P aO2 ) a.Anemia b.Carbon Monoxide c.Hypoperfusion (CV problem) Local Control a.Low P AO2 vasoconstriction b.Low P VCO2 bronchoconstriction

57 Fourth Ventricle Nucleus retroambiguous (ventral) Nucleus tractus Solitarius (dorsal) C1 Medulla Oblongata C Cut-off B vent A Insp Dors ts Pneumotaxic Center Apneustic Center – Periph & Central Chemo- receptors + Respiratory Muscles + + Vagus Stretch + Tonic Insp Drive + Cut-off signal thresh

58 Arterial P O2 (mm Hg) % maximal firing rate Peripheral Chemoreceptor Responsiveness

59 BBB CSFPlasma CO 2 HCO 3 + H + CO 2 HCO 3 + H + Pumped Respiratory Acidosis ( P aCO2 ) CNS Acidosis then HCO 3 is pumped in (& restores pH CNS faster than kidneys can restore pH systemic )

60 BBB CSFPlasma CO 2 HCO 3 + H + CO 2 HCO 3 + H + Metabolic Acidosis Hyperventilation & P aCO2 CNS Alkalosis !!!! (then pump HCO 3 out)

61 Ventilatory Response to O 2

62 Ventilatory Response to CO 2

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65 BBB CSFPlasma CO 2 HCO 3 + H + CO 2 HCO 3 + H + Respiratory Alkalosis high pH CSF limits Hyperventilation When pH CNS returns to norm (HCO 3 pumped out) V E is less restrained


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