So, 36.7 degrees Celsius, if our temperature increases or decreases even slightly, our proteins basically lose their efficiency and cannot function properly. So what our body does is it uses the skin to actually maintain thermal regulation via the process of sweating, perspiration as well as evaporation and radiation, as we'll see in just a moment. So every exothermic process that takes place in the body for example, let's say cellular respiration produces excessive amounts of energy, excessive amounts of heat. And if that heat is not expelled by that body, it will increase the core temperature. And what that means is our body must actually get rid of that heat. And what it does is it takes the heat and it stores that heat in our blood.