Its action is described as being complementary to that of the sympathetic nervous system, which is responsible for stimulating activities associated with the fight-or-flight response. Nerve fibres of the parasympathetic nervous system arise from the central nervous system. Specific nerves include several cranial nerves, specifically the oculomotor nerve, facial nerve, glossopharyngeal nerve, and vagus nerve. Three spinal nerves in the sacrum (S2-4) also act as parasympathetic nerves.
A healthy BMI is considered to be between 18.5 and 24.9. Based on these BMI tables, the National Heart, Lung and Blood Institute suggests that a healthy weight range for women who are 5 feet 4 inches tall is 110 to 140 pounds.
Most women who exercise regularly and are in good condition are included in the healthy body fat range. Women ages 19 to 29 whose body fat is between 19 to 22 percent are included in the healthy range. Also included are women ages 30 to 39 with body fat between 20 to 24 percent.