Which 3 are correct?


a) Intrapleural pressures are always negative during normal tidal breathing
b) Intrapulmonary pressures are always negative during normal tidal breathing
c) Intrapulmonary pressures are + on inspiration - expiration
d) Intrapulmonary pressures are + on expiration - inspiration
e) Intrapleural pressures are + on expiration - inspiration
f) Intrapleural pressures are + on inspiration - expiration
g) Intrapulmonary pressures can be positive with valsalva and forced expiration
h) Intrapleural pressures can be positive with valsalva and forced expiration