autonomic nervous system

n. (ANS) Literally, the system of self-knowledge. ANS is a division of the body’s neural systems which has the role of regulating involuntary activity of the glands, internal organs including the heart, and the smooth muscles of the vasculature. The ANS’s multiple, well- coordinated effects are slow and widespread, operating through an extensive network of neurons.

The ANS is divided into two major divisions. The action of each division tends to be opposite the other division’s in direction, moving toward physiological balance, or equilibrium. The sympathetic nervous system (SNS) tends toward catabolism, the expenditure of energy, whereas the parasympathetic system tends toward anabolism, the storage of energy. Central nervous system (CNS) activity monitors ANS activity, so that when one of the divisions of the ANS is actively stimulated, the other division is less active, thus encouraging clarity of response to autonomic stimulation.

There is also an enteric division of the ANS in the lining of the esophagus, stomach, and intestinal region, which controls the transport and digestion of food in the digestive tract.

The ANS was once considered to be selfregulating, and not subject to conscious cognitive influence. Extensive biofeedback studies have demonstrated, however, that several autonomic functions, such as blood pressure and brain wave activity, can be modified by the CNS through cognitive processes.