PHYSIOL 201 Lecture Notes - Lecture 27: Airway Resistance, Transpulmonary Pressure, Elastic Fiber
3 May 2019
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Document Summary
Increased non-elastic collagen; i. e. fibrosis: high surface tension; i. e. inadequate surfactant, difficult to inspire adequate volumes. It equalizes the pressures between alveoli of different sizes. Surfactant keeps alveoli from collapsing, particularly it keeps small alveoli from collapsing into bigger alveoli: without surfactant, the work of breathing would be exhaustive, so muscle fatigue and respiratory failure would occur quickly. If tv is decreased, what happens to delta p: reducing surface tension reduces the effort required to breath, fibrosis very stiff walls that get thicker and stiffer over time; can be fatal. Not usually: airway resistance is usually quite low, smooth muscle around them can constrict or dilate airways. Airway dilators: airway smooth muscle will relax. Situations in which airway r might change: cold or hot air could be an irritant, aerobic exercise natural bronchodilator (epinephrine increases circulation while exercising, exercise, airway r decreases due to increased circulating epinephrine.
