ABSTRACT
Introduction T he internal regulation system consists o f neurons and pathways that control functions necessary for survival o f the individual and the species. These neurons are locat ed at supratentorial, posterior fossa, spinal, and periph eral levels. T he internal regulation system controls vis ceral, endocrine, and motor functions that maintain the internal environm ent and allow bodily adaptation in response to challenges from the external environment. These functions include 1 ) maintenance o f blood flow to tissues, 2 ) regulation o f the composition o f the blood to provide an adequate internal environment for cell func tion (homeostasis), 3) adaptive responses to external and internal challenges, including stress and emotional reac tions, 4) regulation o f immune function, 5) modulation of pain sensation, and 6 ) reproductive behavior.
