The bodies response to stress - Chronic stress

Chronic stress - The pituitary-adrenal system 

The pituitary-adrenal system has traditionally been seen as the body's 'stress system', controlling levels of cortisol (CORT) and other important stress-related hormones. 

The role of the hypothalamus:

When stressors are perceived by the higher centres of the brain, a message passes to a small cone-shaped part of the brain, the hypothalamus. The hypothalamus is the control system for most of the body's hormonal systems, including those involved in the stress response. Activation of a particular region of the hypothalamus, the paraventricular nucleus (PVN) leads to the production of a chemical messenger, corticotrophin-releasing factor (CRF), which is released into the bloodstream in response to the stressor.

The pituitary gland:

CRF causes the pituitary to produce and release adrenocorticotrophic hormone (ACTH). From the pituitary, ACTH is transported in the bloodstream to its target site in the adrenal glands,located on top of the kidneys.

The adrenal cortex:

Cortisol, released by the adrenal cortex, is responsible for several stress-related effects in the body. Some of these are positive, whereas others are negative. Prolonged release of ATCH causes the adrenal cortex to increase in size in order to cope with increased cortisol production. Long-term ACTH deficiency causes it to shrink.