Endocrine System also referenced as the Hormonal regulatory system, represents another primary survival system addressed by N.O.W. 

The Endocrine system is the non-neural communication system in the body and brain.  Common hormonal systems are the Adrenal, Thyroid, and Reproductive.

Any insult or stressor to the body/CNS will trigger a response of the endocrine system to assist the physical body adapt to the change.  The most common stressor is emotional stress.