ABSTRACT
The Hypothalamus-Pituitary-Adrenal (HPA) axis is organized into three distinct regions: the hypothalamus, pituitary gland and adrenal gland. It is a complex set of direct influences and feedback interactions among the three endocrine glands. The HPA axis plays an important role under stressed conditions, because the released hormones lead to energy directed to the organisms. Therefore, the dynamics of the HPA axis is very important. Lately, several models of HPA axis have been developed [3], [4], [5], [6].
