The HPA axis
The hypothalamic pituitary adrenal (HPA) axis is our central stress response system. If a situation is judged as being stressful, the hypothalamus is activated and takes charge of the stress response.

- The stressor activates the Hypothalamic Pituitary Axis.
- The hypothalamus stimulates the pituitary gland.
- The pituitary gland secretes adrenocorticotropic hormone (ACTH).
- ACTH stimulates the adrenal glands to produce the hormone corticosteroid.
- Cortisol enables the body to maintain steady supplies of blood sugar.
- Adequate and steady blood sugar levels help person to cope with prolonged stress, and helps the body to return to normal.

Parts of the brain involved
Where there is a chronic or constant stress, threat or repeated trauma the system remains activated. This can lead to an alteration of the body’s response to stressors, immunity, inflammation, metabolism, hormone balance, energy, emotions, mood, sexuality and other important processes.
The diagram below shows the different parts of the brain that are involved in the HPA Axis.
