Responses To Stress

Sympathomedullary pathway (SAM)

1. Hypothalamus is activated by stressor
2. Recognises it as acute stress; activates the sympathetic branch of the autonomic nervous system (ANS)
3. This stimulates the adrenal medulla in the adrenal gland just above the kidneys
4. secretes adrenaline and noradrenaline
5. these hormones prepare body for fight or flight by making physical changes e.g increased heart rate, blood pressure, blood flow to muscles etc 
6. Parasympathetic rebound: body cannot maintain increased level of activity for long periods (too much energy) so parasympathetic branch is activated
7. countershock response that serves to return body back to natural resting state

Hypothalamic pituitary adrenal system (HPA axis)

1. Stressor activates the hypothlamus

2. Recognises it to be chronic stress

3. Activates the HPA axis; also known as the pituitary gland system

4. This stimulates the pituitary gland in the brain

5. The PG causes the release of hormones such as adrenocorticotrophic                hormone (ACTH)

6. This stimulates the adrenal cortex (another part of adrenal glands) to release corticoteroids (key one= cortisol)

7. Has physiological effect on body

8. (+) constant supply of energy to muscle

 (-) supression of immune system as a way of conserving energy