Final answer:
The best index of oxygen transport is the CaO2, as it accounts for the total oxygen carrying capacity of the blood, including both the oxygen bound to hemoglobin and the oxygen dissolved in plasma. option c is correct
Step-by-step explanation:
option c is correct The best index of oxygen transport in the body is indicated by c. CaO2 (oxygen content of arterial blood). This is because it provides a measure of how much oxygen is actually being carried by the blood, including the oxygen bound to hemoglobin as well as the oxygen dissolved in the plasma. The majority of oxygen in the blood is transported by hemoglobin and oxygen, with about 98% of oxygen binding reversibly to the respiratory pigment hemoglobin found in red blood cells (RBCs). Additionally, carbon dioxide is transported in three major mechanisms: by blood plasma, as bicarbonate (HCO3), and by binding to proteins or hemoglobin.
In contrast, PaO2 is the partial pressure of oxygen in arterial blood, PAO2 is the partial pressure of oxygen in the alveoli, and SaO2 is the arterial oxygen saturation. While these measures are important, they do not account for the total oxygen carrying capacity of the blood to the same extent as CaO2.
The best index of oxygen transport is PaO2 (partial pressure of oxygen in arterial blood).
PaO2 reflects the amount of dissolved oxygen in the blood, which is important for oxygen delivery to the tissues. A higher PaO2 indicates better oxygenation.
For example, in healthy individuals, PaO2 ranges from 75 to 100 mmHg.