Part of “CHAPTER 85 – PHYSIOLOGY OF THE ADRENAL MEDULLA AND THE SYMPATHETIC NERVOUS SYSTEM“

The chromaffin tissue of the adrenal medulla and that of the ganglia of the sympathetic nervous system share an embryonic origin from neural crest tissue. The term chromaffin refers to the histochemical identification of intracellular granules that turn brown when treated with oxidizing agents. In adult humans, chromaffin cells exist mainly in the adrenal medulla because sympathetic nerve terminals do not occur in a form concentrated enough to produce a detectable chromaffin reaction.