The partial pressure of carbon dioxide is greatest in_____
The correct answer and explanation is :
The partial pressure of carbon dioxide (pCO₂) is greatest within the cells of peripheral tissues, where it reaches approximately 50 mmHg. This elevated pCO₂ results from cellular metabolism, which continuously produces carbon dioxide as a byproduct.
In the process of internal respiration, carbon dioxide diffuses from areas of higher partial pressure in the tissues into the capillary blood, where the pCO₂ is lower, typically around 45 mmHg. This diffusion is driven by the concentration gradient between the tissues and the blood.
As blood circulates back to the lungs, it carries carbon dioxide to the alveoli, where the pCO₂ is approximately 35 mmHg. Here, carbon dioxide diffuses from the blood into the alveolar air and is expelled from the body during exhalation.
Understanding these variations in pCO₂ is crucial for comprehending gas exchange dynamics and the body’s regulation of acid-base balance. The gradient of carbon dioxide partial pressures facilitates its efficient removal from the body, ensuring that metabolic waste does not accumulate to harmful levels.
