PHYSIOL 201 Lecture Notes - Lecture 20: Phospholipid, Transpulmonary Pressure, Paracrine Signalling
Document Summary
Alveolar pressure is the pressure that is being changed, not atmospheric pressure. Normal expiration is passive and requires no muscle contraction; it is just relaxation of the lung muscle. Forced expiration requires contraction of different muscle and causes it pressure to go up. Know the equations for minute and alveolar ventilation. Minute ventilation is just frequency times tidal volume (total amount of air that is being moved) The important volume that is being moved is the one that reaches the alveolar because this is where gas exchange is going to occur. You can move a large volume of air total but still not ventilate your alveolar well (such as taking really fast and shallow breaths, which will cause you to ventilate primarily your dead space) The characteristics of the lungs and airways can contribute to how much air is capable of moving. If the lungs are more/less stretchy, it will affect the volume of air that is moved.
