In terms of carbon dioxide transport, how does CO2 move from the cells to the lungs?

Carbon dioxide (CO2) is primarily transported from the cells to the lungs through the process of diffusion. When cells metabolize nutrients, they produce CO2 as a waste product, which creates a higher concentration of CO2 in the tissues compared to the concentration in the blood. This concentration gradient facilitates the movement of CO2 from the areas of higher concentration (the tissues) to areas of lower concentration (the blood).

Once CO2 enters the bloodstream, it travels through interstitial fluid and subsequently within the blood, where approximately 70% of it is converted into bicarbonate (HCO3-) for transport, while a smaller percentage is dissolved in plasma and binds to hemoglobin in red blood cells. This passive process of diffusion continues as CO2 moves through the vasculature towards the lungs, where it diffuses across the alveolar-capillary membrane into the alveoli to be exhaled.

The other methods mentioned, such as movement through the lymphatic system and active transport mechanisms, are not involved in the typical transport of CO2 from cells to the lungs. CO2 travel through the lymphatic system is not significant because this system is primarily responsible for transporting lymph fluid and immune cells, not gases. Active transport, which requires energy, is