Why do our eyes roll back when we feel pleasure?

The rolling back of eyes is a sign our body gives us that it is now the time to relax. When a person faints, becomes unconscious or experiences extreme pleasure, the human nervous system sends out some signals which force the  body shut down certain body parts to focus on pleasurable sensation. This happens to your eyes too, when our eye muscles completely relax and they roll out.

So  if  the sum of the enthalpies of the reactants is greater than the products, the  reaction  will be  exothermic.  if  the products side has a larger enthalpy, the  reaction  is  endothermic. you may wonder why  endothermic reactions, which soak up energy or enthalpy from the environment, even happen