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Trachea (Generation #1) Primary Bronchi (Generation #2)

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Presentation on theme: "Trachea (Generation #1) Primary Bronchi (Generation #2)"— Presentation transcript:

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

2 Zone 1 PA>Pa>Pv Low Flow Flow=P/R Zone 2 Pa>PA>Pv
Waterfall Zone 3 Pa>Pv>PA Hi Flow O2 CO2 venous arterial PB=0 PA<0 Flow=P/R

3 Atmospheric Air High O2 (150 mmHg) CO2 ~ 0 Inspiration Expiration
PB=0 PB=0 Inspiration Expiration Alveolar Air O2 ~100 mmHg PA<0 PA>0 CO2 ~ 40 mmHg O2 O2 venous arterial venous arterial CO2 CO2

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

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

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

8 V1 V1 C1V1=N C2(V1 +VL) =N VL VL VL=(C1/C2)V1 –V1 C1V1= C2(V1 +VL)
Equilibrate Concentration C1V1=N C2(V1 +VL) =N VL VL VL=(C1/C2)V1 –V1 C1V1= C2(V1 +VL)

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

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

13 Balance of Forces Determines FRC
Hooke’s Law: F = -kx Chest Wall Recoil Force Increasing volume Intrapleural space Ppl = -2 Normal FRC Ppl = -5 Ppl= -8 Lung Wall Recoil Force Decreasing volume Ppl = 0 Emphysema  lung recoil Fibrosis  lung recoil Pneumo- thorax Normal

14 LaPlace 2T=Pr P=2T/r For same T, P1>P2 (I.e. 2T/r1 > 2T/r2) P1

15 Surface Area (relative)
Surface Area  Surface Tension Lung Surfactant Plasma Surfactant 40% Dipalmitoyl Lecithin 25% Unsaturated Lecithins 8% Cholesterol 27% Apoproteins, other phospholipids, glycerides, fatty acids Surface Area (relative) Detergent Water 30 60 80 Surface Tension (dynes/cm)

16 Surface Area (relative)
Surface Area  Surface Tension Lung Surfactant Reduces Work of Breathing Increases Alveolar Stability (different sizes coexist) Keeps Alveoli Dry Surface Area (relative) Detergent Water 30 60 80 Surface Tension (dynes/cm)

17 Static Compliance Curves
Expiration Inspiration

18 Static Compliance Curves

19 Balance of Forces Determines FRC
Hooke’s Law: F = -kx Chest Wall Recoil Force Ppl = 0 Ppl = -2 Emphysema  lung recoil Fibrosis  lung recoil Pneumo- thorax Ppl= -8 Increasing volume Intrapleural space Normal FRC Ppl = -5 Lung Wall Recoil Force Decreasing volume Normal

20 Chest Wall Apex -8 -5 Lung has weight Base Ppl = -2

21 Regional- Apex to Base Differences

22 Regional- Apex to Base Differences

23 Apex to Base Differences

24 Respiratory Cycle - Ppl time Respiratory Cycle Single VT Breath -5
VT (L) 0.4 Respiratory Cycle Single VT Breath 0.2 -5 Rest FRC Air Flow Inspiration Expiration -8 Inspiration - -5 Ppl (cm H2O) End Inspiration PB=0 -8 PA= 0 + -6 Expiration -8 +0.5 End Expi- ration-FRC Air Flow (L/s) -5 The linear Dashed trace is the Ppl required to overcome recoil forces. More Ppl (solid curve) is required to overcome airway resistance to flow. N.B. P = PA-PB  Resist•Flow. -0.5 +1 PA (cm H2O) -1 time (sec)

25 Static Compliance Curves
Expiration Inspiration

26 Respiratory Cycle - Ppl time Respiratory Cycle Single VT Breath -5
VT (L) 0.4 Respiratory Cycle Single VT Breath 0.2 -5 Rest FRC Air Flow Inspiration Expiration -8 Inspiration - -5 Ppl (cm H2O) End Inspiration PB=0 -8 PA= 0 + -6 Expiration -8 +0.5 End Expi- ration-FRC Air Flow (L/s) -5 Case of ZERO Resistance -0.5 +1 PA (cm H2O) -1 time (sec)

27 Respiratory Cycle - Ppl time Respiratory Cycle Single VT Breath -5
VT (L) 0.4 Respiratory Cycle Single VT Breath 0.2 -5 Rest FRC Air Flow Inspiration Expiration -8 Inspiration - -5 Ppl (cm H2O) End Inspiration PB=0 -8 PA= 0 + -6 Expiration -8 +0.5 End Expi- ration-FRC Air Flow (L/s) -5 The linear Dashed trace is the Ppl required to overcome recoil forces. More Ppl (solid curve) is required to overcome airway resistance to flow. N.B. P = PA-PB  Resist•Flow. -0.5 +1 PA (cm H2O) -1 time (sec)

28 Respiratory Cycle - Ppl time Respiratory Cycle Single VT Breath -5
VT (L) 0.4 Respiratory Cycle Single VT Breath 0.2 -5 Rest FRC Air Flow Inspiration Expiration -8 Inspiration - -5 Ppl (cm H2O) End Inspiration PB=0 -8 PA= 0 + -6 Expiration -8 +0.5 End Expi- ration-FRC Air Flow (L/s) -5 Case of HIGH Resistance -0.5 +1 PA (cm H2O) -1 time (sec)

29 Dynamic Compression of Airways
Mild Expiratory Effort (P+13) -5 Normal at FRC PTP=+5 PPl - PA= -5

30 Dynamic Compression of Airways
+13 Mild Expiratory Effort (P+13) +8 8 4 Normal at FRC - 5 PTP=+5 PPl - PA= -5 Strong Expiratory Effort (P+30) +25 30 5 EPP Normal EPP Equal Pressure Point (in supported airways) 4 2 EPP Emphysema +11 P Pl - A = +28 EPP Emphysema in unsupported airways Low VL& Basal Alv also like this

31 Total Cross Sectional Area
Airway Generation Resistance Subsegmental Bronchi 8l R= ——— r4 k•number R= ————— A2 Airway Generation Total Cross Sectional Area Conducting Zone Resp v = Flow/A NR= Dv/ =density D= diameter v= velocity = viscosity

32 Lung Volume Airway Resistance Normal Recoil Emphysema Fibrosis

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

34 Forced Vital Capacity Obstructive Restrictive Normal TLC
FEV1.0 FVC 1 sec FEV1.0 = 1.2 L FVC = 3.0 L % = 40% RV Obstructive airway resist Restrictive lung recoil TLC FEV1.0 FVC 1 sec FEV1.0 = 2.7 L FVC = 3.0 L % = 90% RV Normal TLC FEV1.0 FVC RV 1 sec FEV1.0 = 4 L FVC = 5 L % = 80%

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

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

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

38 Critical Closing Volume Test TLC RV
4. 40 1. 2. Dead Space Washout 3. Alveolar Plateau N2 Concentration (%) 20 Closing Volume Lung Volume (L)

39 Apex to Base Differences

40 Critical Closing Volume Test TLC RV
Increased Closing Volume 4. 40 1. 2. Dead Space Washout 3. Alveolar Plateau N2 Concentration (%) 20 Closing Volume Lung Volume (L)

41 PO2=100 mm Hg 21 ml O2/dL PO2=100 mm Hg 21 ml O2/dL O2 O2 PO2=100 mm Hg 0.3 ml O2/dL PO2=100 mm Hg 0.3 ml O2/dL dissolved 20 ml O2/dL HB-O2 O2 O2

42 Expired Lung Volume (L) N2 Concentration (%)
Alveolar Plateau Inspired O2 diluted by alveolar N2 N2 Concentration (%) 20 40 A B Fowler’s Test Area A = Area B Vd

43 E.Alveolar Ventilation . . . VE = VD + VA = VT  frequency
The Bohr Equation VD1 (PACO2 – PECO2)  =  VT PACO2 VD2 (PaCO2 – PECO2)  =  VT PaCO2 D. Sample Calculation VT = 600 ml PACO2 = 38 mmHg PECO2 = 28 mmHg PaCO2 = 40 mmHg VD1 = 600(38 – 28)/38 = 158 ml VD2 = 600(40 – 28)/40 = 180 ml E.Alveolar Ventilation VE = VD + VA = VT  frequency VA = VE - VD . 1.For VT = 500 ml, f = 10/min, VD = 150 ml, what is VA? . VA = = 3500 ml/min If VE is doubled by increasing VT what is VA? = 10, = 8500 ml/min If the same VE is obtained by doubling frequency, what is VA? = 10, = 7000 ml/min . Thus increasing VT rather than frequency is more effective for  VE.

44 F. Alveolar Ventilation and CO2 production
VCO2 = Expired CO2 - Inspired CO2 . =VA  FACO2 VA x PACO2 =  PA . .VCO2  K VA =  PACO2

45 XIV. RESPIRATORY GAS CASCADE
PO2 PCO2 mm Hg mm Hg  Air (dry) 760  Trachea (humidified; ) 713  Alveolus (some O2 absorbed by blood) Arterial (R-L Shunt) Mixed venous (O2 absorbed by tissues) 40 46

46 O2 Diffusion in Pulmonary Capillaries
(transit time) 100 Thickened Alveolar Membrane 80 60 PO2 mm Hg Normal Transit Time 40 Exercise Shortens Transit time 20 0.25 0.5 0.75 time in Capillary (sec)

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50 CO2 Loading & O2 Unloading
Tissue CO2 Loading & O2 Unloading CO2 O2 Capillary Wall Cl- O2 CO2 c.a. CO2 + H2O — H2CO3  H+ + HCO3- H+ + HbO2  HHb + O2 Carbamino HHb-CO2

51 CO2 Unloading & O2 Loading
Lungs CO2 Unloading & O2 Loading CO2 O2 Alveolar Wall O2 CO2 HCO3- Cl- c.a. CO2 + H2O — H2CO3  H+ + HCO3- H+ + HbO2  HHb + O2 Carbamino HHb-CO2

52 HALDANE SHIFT Rest Venous P (mm Hg) CO Content (ml CO /100 ml blood)
37 40 43 46 49 52 48 50 54 Rest Venous P CO2 (mm Hg) CO 2 Content (ml CO /100 ml blood) HALDANE SHIFT Exercise Venous O2 helps CO2 unloading Arterial (O2)

53 Ventilation Perfusion Ratios
PO2 = 150 PCO2 = 0 PO2 = 40 PCO2 = 45 PO2 = 100 PCO2 = 40 PO2 = 150 PCO2 = 0 No flow CO2 = 45 . . . Low VA/Q Normal VA/Q High VA/Q

54 50 Low VA/Q Base Apex Normal VA/Q PCO2 (mm Hg) High VA/Q 50 100 150
PO2 = 40 PCO2 = 45 PO2 = 100 PCO2 = 40 50 Low VA/Q . Base Apex PO2 = 150 PCO2 = 0 Normal VA/Q . PCO2 (mm Hg) High VA/Q . 50 100 150 PO2 (mm Hg)

55 Perfusion Flow of Blood or Air VA/Q VA/Q Ratio Ventilation Top Bottom
3 Perfusion . VA/Q 2 Flow of Blood or Air . VA/Q Ratio Ventilation 1 Distance up Lung Bottom Top . .

56 Mechanisms of Hypoxemia
PaO2 PaCO2 PO2 (A-a) PaO2 with 100% O2  Hypoventilation low High Norm >550 Diffusion low norm-low high >550 R-L Shunt low norm-low high < VA/Q Imbalance low norm-lo-hi high >550 Other Hypoxemias (without low PaO2) Anemia Carbon Monoxide Hypoperfusion (CV problem) Local Control Low PAO2  vasoconstriction Low PVCO2  bronchoconstriction

57 C A B Pneumotaxic Center – + Apneustic Center Periph & Central Chemo-
Fourth Ventricle Nucleus retroambiguous (ventral) 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 signal thresh

58 Peripheral Chemoreceptor Responsiveness
75 50 % maximal firing rate 25 50 100 500 Arterial PO2 (mm Hg)

59 Plasma BBB CSF CO2 HCO3 + H+ CO2  HCO3 + H+ Pumped CNS Acidosis
then HCO3 is pumped in (& restores pHCNS faster than kidneys can restore pHsystemic) Respiratory Acidosis (PaCO2)

60 Plasma BBB CSF CO2 HCO3 + H+ CO2  HCO3 + H+ CNS Alkalosis !!!!
(then pump HCO3 out) Metabolic Acidosis Hyperventilation & PaCO2

61 Ventilatory Response to O2

62 Ventilatory Response to CO2

63 Ventilatory Response to CO2

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65 Plasma BBB CSF CO2 HCO3 + H+ CO2  HCO3 + H+ When pHCNS
returns to norm (HCO3 pumped out) VE is less restrained Respiratory Alkalosis high pHCSF limits Hyperventilation


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