Since we are talking about interactions with the nervous system, how do we go from the pressure at which these gasses were delivered to the alveoli to their behavior in the blood?

I understand the practice GP is describing pretty well but when I try to simulate what is going on in my mind, it's not like these gasses are in gaseous form once they are in the blood. Are we just talking about the concentration that are reached because the pressure affects the diffusion gradient?