KINE 3012 Chapter Notes - Chapter 13.5: Smooth Muscle Tissue, Airway Resistance, Respiratory Disease
11 Feb 2018
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Document Summary
Emphysema: characterized, collapse of smaller airways, breakdown of alveolar walls. Irreversible condition: results from excessive release of destructive enzymes-trypsin- from alveolar macrophages as in response to smoke & irritants. Lungs normally protected from damage by enzymes which inhibits trysin. Excessive secretion overwhelms enzymes: destructive enzymes damage lung tissue, breakdown of alveolar walls, collapse of small airways, arises from genetic inability to produce antitrypsin. Difficulty in expiration: pulmonary disease increases airway resistance, expiration more difficult than inspiration, airway resistance lower in inspiration than expiration, airways may collapse during expiration. Lung elasticity: pulmonary elasticity involves: compliance & elastic recoil, compliance: how much effort is required to stretch lungs. Change in lung volume from change in transmural pressure gradient. Transmural pressure gradient is force that stretches lungs. Highly compliant lung stretches more to increase in pressure difference. Lower compliance of lung means larger transmural pressure gradient required during inspiration to expand lung. Larger transmural achieved during inspiration by making intrapleural more subatmospheric.
