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94 Cards in this Set
- Front
- Back
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Lung Volume and Capacities
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113
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tidal volume definiton
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norm volumen of inspiration/expiration
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insp reserve volume definition
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volume inspired over tidal
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exp reserve volume defnition
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volume expired after tidal
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Residual vol
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remains after max exp; can't be measured by spirometry
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Norm anatomic dead space equals
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150 mL
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physiologic dead space eqn
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Vd = Vt x (PACo2-PECO2/PACO2)
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min vent eqn
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tidal vol x resp rate
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alveolar vent eqn
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(tidal vol - dead space) x resp rate
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IC (insp capacity) equals
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Vt + IRV
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FRC (func residual capacity) equals
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ERV + RV
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VC (vital capacity) equals
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Vt + IRV + ERV
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FEV1/FVC usu equals
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0.8
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fx of obstructive lung dz on FEV1/FVC
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dec
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fx of restrictive lung dz on FEV1/FVC
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norm or inc
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Breathing Mechanisms
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115
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compliance eqn
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C = V/P
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compliance is inversely related to
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elastance
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transmural pressue eqn
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alv pressure - intrapleural pressure
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difference of inspiration and expiration curve is called
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hysteresis
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compliance is greatest over which pressures
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middle range
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at FRC, lung collapsing force and chest expanding force are
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equal and opposite
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lung collapsing and chest expanding forces create
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negative intrapleural pressure
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in emphysema, lung compliance is
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inc
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tendency of lung collapse in emphysema is
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dec
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result on FRC w/ emphysema
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new higher FRC
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in fibrosis, lung compliance is
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dec
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tendency of lung collapse in fibrosis is
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inc
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result on FRC w/ fibrosis
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new lower FRC
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Laplace law
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collapsing pressure on alveolus = 2(surface tension)/radius
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is it easier to keep open a large or small alveolus
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large
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collapsing of alveoli is called
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atelectasis
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flow eqn
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Q = DP/R
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Poiseuille's law
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R = 8hl/pr^4
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PNS fx on airway resistance
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inc (by dec radius)
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SNS fx on airway resistance
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dec (by inc radius)
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high lung volumes fx on airway resistance
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dec (greater traction)
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low lung volumes fx on airway resistance
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inc (less traction)
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denser gas fx on airway resistance
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inc (higher viscosity)
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less dense (He) gas fx on airway resistance
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dec (lower viscosity)
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before breathing begins, alveolar pressure is
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0 (equal to atm)
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on inspiration, alveolar pressure is
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less than atm
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on expiration, alveolar pressure is
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greater than atm
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during forced expiration, intrapleural pressure is
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positive (making expiration harder)
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Gas Exchange
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122
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fractional conc of O2 is
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21% (0.21)
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in humidified tracheal air, modified total pressure becomes
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760-47 = 712 mmHg
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cardiac output that bypasses pulm circ
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physiologic shunt
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gases demonstrating perfusion-limited exchange
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N2O, O2
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gases demonstrating diffusion-limited exchange
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CO, O2 during exercise
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gas does not equilibriate by the time blood reaches end of pulm cap
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diffusion-limited exchange
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Oxygen/CO2 Transport
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123/129
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shape of Hb-O2 curve
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sigmoidal
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what gives Hb-O2 curve its shape
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positive cooperativity
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what part of Hb-O2 curve is flat
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b/t 60-100 mmHg
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Hb-O2 curves shifts right when: 4
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inc PCO2, dec pH, inc temp, inc 2,3-DPG
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Hb-O2 curves shifts left when: 4
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dec PCO2, dec temp, HbF, CO
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A-a gradient equals
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PAO2 - PaO2
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Alv gas eqn
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PAO2 = PiO2 - PACO2/R
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Norm A-a gradient
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<10 mm Hg
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O2 delivery equals
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CO x O2 content of blood
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main form CO2 transported to lung
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HCO3
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H+ in RBC buffered by
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deoxyHb
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CO2 rxn in body
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CO2 taken up -> combine w/ H2O -> H2CO3 -> H+ + HCO3 -> HCO3 exchanged for Cl
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CO2 rxn in lung
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HCO3 exchanged for Cl -> combine w// H+ -> H2CO3 -> H2O + CO2 -> expired CO2
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Pulm Circ & V/Q defects
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129
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pressures and resistances in pulm circ v. systemic
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both are much lower (flow the same)
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pulm blood flow is
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cardiac output of RV
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highest flow in
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zone 3 (base)
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highest ventilation in
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zone 3 (base)
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highest V/Q in
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zone 1 (apex)
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highest PO2 in
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zone 1 (apex)
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highest PCO2 in
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zone 3 (base)
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with pulm shunt, V/Q is
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low (blocked vent)
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with dead space, V/Q is
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high (blocked prefusion)
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Breathing control
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132
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medullary resp center is in the
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reticular formation
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dorsal resp group is responsible for 2
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inspiration; breathing rhythm
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inputs to dorsal resp group 3
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CN X (peripheral chemo-R, mechano-R), CN IX (peripheral chemo-R)
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output from dorsal resp group 1
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phrenic nerve
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ventral resp group is responsible for 1
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expiration during exercise
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apneustic center is located in
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lower pons
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role of apneustic center
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stim inspiration (prolonged deep gasp)
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pneumotaxic center located in
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upper pons
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role of pneumotaxic center
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inh inspirtation (regulates insp vol & resp rate)
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chemo-R in medulla sense
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pH of CSF (CO2)
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chemo-R in carotids/aortic arach sens
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blood pH (CO2 & O2 < 60)
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lung stretch R are located in
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airway SM
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Reflex induced by lung stretch
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dec freq (Hering-Breuer)
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J-R are located in
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alv walls (close to cap)
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reflex induced by J-R
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rapid shallow breathing when pulm cap are engorged
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does arterial pH change during moderate exercise
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no (only w/ lactic acidosis from extreme exercise)
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does venous pH change during exercise
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yes, PCO2 inc
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adaptation to high alt? 4
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hypoxemia -> peripheral chemo-R (hypervent), renal (EPO), 2,3 DPG, pulm vasoconstriction
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