The Superficial Immune system as i call it, can be thought of as the glue that holds life together and is the most complex due to its dynamic homeostatic nature. 

The superficial immune system is the most active system neutralizing bacteria in the digestive system, the common cold(s), and infections from skin wounds.

It also plays an active role in tissue repair and cellular growth.

T.M.J. is referenced above relative to digestion in its function of biting and chewing as the first stage of digestion.  These movements are also responsible for activation of two hormones (secretin & gastrin) that ready the small and large intestine for continuing digestion. Thus the coordinated movements of the jaw plays a direct role in digestive function.

The jaw (T.M.J.) also plays an additional function in survival.  That functional role is of a filtering mechanism vital to survival.  The left jaw protects us from overwhelming physical pain and physiological stress and the right jaw protects us from overwhelming emotional stressors.