Abstract
This chapter provides an overview on the multiple mechanisms by which the nervous system regulates and directs immune function towards what is needed and tolerated by the nervous system. The immune system plays two essential roles necessary for the survival of complex organisms, including tissue homeostasis and tissue defense against pathogens. These immune functions are essential to maintain the functions of all organs in the body and are studied as a part of the general field of immunology. The immune system is divided into two arms: a rapid “innate” immune response system and a slow “adaptive” immune response system. The receptors for the types of “alarm” signals detected by the innate immune system are preformed and stably encoded in the genome. By contrast, the receptors for the types of signals that trigger the adaptive immune system are in part stochastically generated and in part shaped by the types and frequency of the pathogens encountered.