1) O2 entering alveoli

2) O2 removal by capillary blood flow

1) am't of CO2 that diffuses into the alveoli from the capillary blood

2) am't of CO2 removal from the alveoli by ventilation

CO2 is washed out of the alveoli faster than it is replaced by venous blood

gas exchange between systemic capillaries and cells

Ratio b/w

O2 consumed and CO2 produced

Gas exchange b/w blood and alveoli

 (bear)

Pulmonary emboli

obstruction

pneumothorax

emphysema

decreased cardiac output

emphysema

pneumonia

pulmonary fibrosis

hypoventilation

DRG

VRG

 very heavy

located in lower pons

 if unrestrained, prolonged inspiration

suppressed by pneumotaxic center