This part of our nervous system handles all of the automatic functions that we don’t even think about such as digestion of food, stimulating the acid to be released in your stomach, regulating the diameter of your lung airways, breathing rate, heart rate, pupil size, sweating, and much more.  It also directly and indirectly helps maintain body temperature, regulate your immune system, and control inflammation.  It has 2 components: the parasympathetic nervous system (PNS) and the sympathetic nervous system (SNS).  They work like a see-saw with each on either end.  Both are active at all times, but what actually happens depends on which one is in the driver’s seat or in control.