6. Partial pressure differences determine gas exchange a. According to law, each gas in a mixture of gases exerts its own pressure as if no other gases were present. b. During external (pulmonary)...

Extracted text: 6. Partial pressure differences determine gas exchange a. According to law, each gas in a mixture of gases exerts its own pressure as if no other gases were present. b. During external (pulmonary) respiration oxygen diffuses from alveolar air, where its partial pressure is _mmHg, into the deoxygenated blood in pulmonary capillaries, where Po2 is _mmHg. Carbon dioxide diffuses from deoxygenated blood, where its partial pressure is _mmHg, into alveolar air, where Pco2 is _mmHg. c. During internal (systemic gas exchange) respiration oxygen diffuses from the systemic capillaries, where its partial pressure is _mmHg, into tissue cells, where Po2 is _mmHg. Carbon dioxide diffuses from tissue cells, where its partial pressure is _mmHg, into systemic capillaries, where Pco2 is mmHg.