Final answer:
The normal partial pressure of oxygen in arterial blood is approximately 75 to 100 mm Hg. This pressure facilitates the transfer of oxygen from the alveoli into the blood. Oxygen partial pressure varies between arterial blood and venous blood due to consumption by body tissues.
Step-by-step explanation:
The normal partial pressure of oxygen in arterial blood, measured in Torr, is about 75 to 100 mm Hg. This value represents the pressure exerted specifically by oxygen within the mixture of gases in the arterial blood. The partial pressure of oxygen is crucial for ensuring adequate oxygen delivery to the body's tissues. In comparison, the partial pressure of oxygen in the alveoli is about 104 mm Hg, and the partial pressure in the blood of the pulmonary capillaries is approximately 40 mm Hg, establishing a gradient that allows for effective gas exchange.
In the context of venous blood and body tissues, the partial pressure of oxygen is generally lower than in arterial blood because oxygen is utilized by the cells, resulting in a lower concentration of oxygen in the venous blood returning to the lungs.