Inspiration/Inhalation
period of time when air is flowing into the lungs
contraction of external intercostals causes ribs to rise and move laterally
contraction of diaphragm causes it to move inferiorly
pulmonary volume increases
Expiration/Exhalation
passive process that depends on the natural elasticity of lungs
inspiratory muscles relax causing ribs to descend and diaphragm to move superiorly
lungs recoil and pulmonary volume decreases
forced exhalation involves contraction of abdominal muscles and internal intercostals
Gas Exchange Physiology
O2 and CO2 is exchanged at pulmonary and systemic capillaries via passive diffusion
diffusion occurs at partial pressure gradients
Partial Pressure Gradients (PPG)
PP- individual pressure exerted by a gas within a mixture of gases (PO2 or PCO2)
G-when PP of a gas differs across a membrane (higher to lower)
Elevated pO2
polycythemia ro higher density atmospheric oxygen
Low pO2
anemia or heart decompensation
Elevated pCO2
pulmonary edema, asthma, or lung obstruction
Low pCO2
hyper ventilation