Final answer:
The parameter denoting arterial oxygen content in blood is CaO₂ - Arterial oxygen content. PaO₂, SaO₂, and PvO₂ represent different aspects pertaining to oxygen in the blood such as partial pressures and saturation levels.
Step-by-step explanation:
The parameter that denotes arterial oxygen content in blood is A. CaO₂ - Arterial oxygen content. The other parameters mentioned, such as B. PaO₂ which represents the partial pressure of oxygen in arterial blood, C. SaO₂ which indicates arterial oxygen saturation, and D. PvO₂ which denotes the partial pressure of oxygen in venous blood, all describe different aspects of oxygen measurement in the blood. CaO₂ specifically refers to the total amount of oxygen in the arterial blood, including both the oxygen bound to hemoglobin and the oxygen dissolved in plasma.
It is essential to understand that in the lungs, oxygen diffuses into the capillaries from the alveoli and binds to hemoglobin in red blood cells, which then transport it throughout the body. In contrast, the PaO₂ value is important because it creates the pressure gradient necessary for oxygen to enter the blood from the alveoli. Similarly, at the tissue level, oxygen is unloaded to the cells, which reflects changes in pressures as indicated by differences in alveolar and capillary partial pressures of both oxygen and carbon dioxide.