The sympathetic division of the autonomic nervous system and the endocrine system are the two prime systems that take part in the stress response.
At the time of acute or chronic stress, the endocrine system first makes the hypothalamus to discharge CRH or corticotropin-releasing hormone into the bloodstream. The release of CRH further makes the anterior pituitary to discharge ACTH or adrenocorticotropic hormone into the blood. This further stimulates the adrenal cortex to discharge cortisol, that is, one of the glucocorticoid hormone into the bloodstream.
The cortisol finally makes the organs and tissues present within the body to effectively cope up with the initial stress stimulus.
Intuitively as it sounds, cyclic change is the change that recurs over a particular period of time. Seasons recur every year in specific regions on earth. In addition, receeding and expanding of ice caps also occur based on seasons. These two are examples of cyclic changes.
