ABSTRACT
This chapter examines an extensive overview of physiological mechanisms that support brain functioning, and adaptive responses to the external environment and internal experiences. Physical and emotional trauma can interfere with these functions acutely. Neurobehavioral success requires that physiological and neurobehavioral functions are coordinated with each other that components of a system operate in sequence and that tissues create and respond to appropriate signals, which are maintained within narrow bounds. The internal milieu is the fluid environment within and surrounding cells: intracellular fluid, extracellular fluid, the bloodstream, and cerebrospinal fluid. The extracellular environments of the neurons and neuroglia are in a steady state with the Cerebrospinal Fluid, an important factor in central nervous system homeostasis. Homeostasis is a survival process functioning to sustain cell survival and function, for example, autonomic functions. Homeostasis implies that there is a body set point, that is, an optimal level for each physiological system, to which functions are returned through bodily mechanisms.
