pulmonary Summary

pulmonary Summary - Muscles of respiration Inspiration...

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Muscles of respiration Inspiration Diapragham attached to lower ribs and spine and contracts downward, innervated by C3-C5 of phrenic nerve (if cut one side, then it moves up, so get paradoxical movement) External intercostal muscles move laterally as you go down and are supplied by spinal cord at same level Scalene muscles in neck elevate first two ribs and sternomastoids raise the sternum Active Expiration Abdominal wall (rectus abdominus, internal/external oblique, transverse abdominus) push diaphragm up Internal intercostal muscles pull ribs down and in (move medially as you go down)
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Equations! V’E Total ventilation Volume of expired gas/unit time Equal to volume of inspired gas normally; increase with V’O2 but then increases more rapidly (blood lactate rate increases greatly) VE=tidal volume x frequency V’A Alveolar ventilation Volume of fresh gas reaching alveoli per minute Generally there is 1:1 relationship between alveolar ventilation and pulmonary blood flow Doubling tidal volume more than doubles alveolar ventilation while doubling frequency just doubles alveolar ventilation V’A=(tidal volume-anatomic dead space) x respiratory frequency Q’ Cardiac output V’O2 Oxygen uptake Increases linearly with work rate but flattens to a max V’O2 Oxygen consumption Fick principle, arterial blood is radial artery and mixed venous blood is pulmonary artery O2 consumption/ min at mouth=amount of O2 taken up by the blood in the lungs per minute V’O2=Q’(CaO2- CvO2) V’CO2 volume of Co2 produce/minute V’I x FICO2=0 V’CO2=(V’x FECO2)- (V’IxFICO2)
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V’gas Fick’s law of diffusion CO2 diffuses more quickly than O2 because it is more soluble V’gas=A/T x D (P1-P2) D=solubility/square root of MW D L for CO Diffusing capacity for CO D L includes the area, thickness and diffusing properties of the tissue sheet and gas concerned D L =V’CO/(P1-P2) is the equation, but CO in blood is small so we take it out. This is low for fibrosis D L =V’CO/(P A CO) 1/D L Diffusion can be lowered by reducing diffusion through the membrane and by slowing the reaction of HbO2 and the reducing flow of blood Diffusion must be calculated adding the diffusion and the reaction with Hb Dm is diffusing capacity of membrane and theta is rate of reaction of O2 with Hb, V is volume of blood in capillary 1/D L =1/D M + 1/(θ xV c ) C g Concentration of gas Henry’s law; k=solubility constant k=C/P (more steep means higher k on C vs P curve) C=k x P O2 capacity Maximum amount of O2 that can be combined with Hb 1.39mL O2 x Hb Oxygen saturation HbO2/O2 capacity x 100 Oxygen concentration of blood 1.39xHb x sat/100 + 0.003pO2
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Capillary pressure Capillary pressure Half way between arterial and venous pressure pACO2 Alveolar pCO2 Alveolar ventilation equation If double alveolar ventilation, half alveolar pCO2 pCO2=vACO2/V’ A x K pAO2 Alveolar pO2 Alveolar gas equation pAO2=pIO2- (pACO2/R) + F R Respiratory exchange ratio CO2 production/O2 consumption If pIO2 decreases
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This note was uploaded on 09/14/2011 for the course PHARM ps taught by Professor Staff during the Spring '11 term at UCSD.

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pulmonary Summary - Muscles of respiration Inspiration...

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