Occurs scar ssue forms and inadequate alveolar

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Unformatted text preview: increases, reaching about 1mm Hg above atmospheric pressure. Alveolar pressure is now higher than atmospheric pressure, so air flow reverses and air moves out of lungs. 4: At end of expira(on, air movement ceases when alveolar pressure is again equal to atmospheric pressure. Lung volume reaches its minimum for the respiratory cycle and is ready to begin again with the next breath. Compliance and Elastance •  Compliance and Elastance –  Compliance: Ability of lung to stretch, or, the amount of force that must be exerted in a body to deform it (a high compliance lung requires less force from the inspiratory muscles to stretch it) –  Elastance: elas(c recoil, or, the ability of a body to return to its original shape when a deforming force is removed •  A lung that stretches easily (high compliance) has probably lost its elas(c (ssue and will not return to its res(ng volume when the stretching force is released (low elastance) –  Old gym shorts: aher many washings, the elas(c band is easy to stretch (high compliance), but lacking in elastance, making it hard for the shorts to stay up around your waist Compliance and Elastance •  Similar problems occur with respiratory system –  Emphysema: disease where elas(n fibers normally found in lung (ssue are destroyed •  Lungs exhibit high compliance and stretch easily during inspira(on •  Lungs exhibit decreased elastance, so they do not recoil during the res(ng por(on of expira(o...
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