In: Anatomy and Physiology
Which environment separated by the respiratory membrane would display the highest oxygen partial pressure?
A)Pulmonary capillary blood
B) Alveolar air
PLEASE EXPLAIN
B) Alveolar air.
Partial pressure are in propotion to the percentage of that gas in a mixture, since the concentrtation of oxygen is higher when you compared to CO2 in alveoli, the alveoli has higher partial pressure of oxygen. The partial pressure of oxygen is greater in alveolar air than deoxygenated blood so oxygen has high tendency to dissolve into deoxygenated blood, while in case of CO2 it is opposite, it has greater partial pressure in deoxygenated blood than alveolar air, so that CO2 wii diffuse into the alveoli to be expelled out.
Partial pressure of oxygen is high in alveoli, it is around 104 mm / hg but partial pressure of oxygen in blood of capillary is about 40 mm / hg, this large pressure difference causes oxygen to diffuse from alveoli into the blood, where as the partial pressure of CO2 is high in pulmonary capillary and low in alveoli as a result CO2 will flow into alveoli to be expelled out.