(A) Oxygen/Carbon di-oxide: Gasous oxygen is required to transport from atomsphere to inside the body. Iron containing hemoprotein such as hemoglobin/myoglobin has active site to bind oxygen. Hemoglobin is present inside the RBC and at the lung surface, it binds oxygen and then inside the body, it release the oxygen in a controlled manner to provide oxygen for running cellular metabolism (Figure 34.1). At the tissue site, it binds CO₂ and release it to atmosphere at the lung surface.

 

Figure 34.1: Gaseous Exchange in animal body