Physiology 3120 Lecture Notes - Lecture 3: Functional Residual Capacity, Tidal Volume, Lung Volumes
Document Summary
Liquid has upside down beaker with gas inside that it connected to pen and paper. Person exhales = more air in beaker = beaker rises up making pen move down. Person inhales = less air in beaker = beaker moves down making pen rise up. Movement of pen indicates volume person is breathing in. Vital capacity is volume between max inspiration and max expiration. As exercise more, irv and erv get smaller. Person does max inspiration so curve starts at top blue line at vital capacity. Person does max expiration as fast as possible so curve falls down get black curve. Measure how much of that vital capacity was exhaled in one second (two red lines) Here 80% of vital capacity was exhaled in first sec and 20% exhaled in remainder. People with asthma have less steep curve = lower fev-1sec (dashed curve) Asthma involves constricted airways and thus takes longer to exhale same amount of vital capacity.