1. What is Stress?
A state of physiological or psychological strain caused by adverse stimuli (physical, mental, internal or external) that tend to disturb the functioning of an organism.

2. Sudden and severe stress generally produces:
Increase in heart rate
Alterations in digestive activity
Skin becomes pale
Sweating increases
Muscular tremors
These responses are produced by the Hypothalamic-Pituitary-Adrenal Axis (HPAA)

3. Physiological Stress Response
The stress response occurs when we are exposed to some sort of threat.
It involves co-ordinated responses from a number of different systems and structures
Hypothalamus
Pituitary gland
Sympathetic ganglia
Adrenal cortex
Adrenal Medulla

4. The Hypothalamus The hypothalamus is in charge of the stress response.
When a stress response is triggered, it sends signals to two other structures: the pituitary gland, and the sympathetic ganglia.
Hypothalamus
Pituitary gland
Sympathetic ganglia
Adrenal cortex
Adrenal Medulla

5. The Pituitary Gland
The pituitary gland controls the glands of the endocrine system.
When activated by the hypothalamus it releases ACTH, which activates the adrenal cortex.
Hypothalamus
Pituitary gland
Sympathetic ganglia
Adrenal cortex
Adrenal Medulla

6. The Sympathetic Ganglia
The sympathetic ganglia are connected to the internal organs. When activated they affect the functioning of the lungs, heart and digestive system.
They are also connected to the adrenal medulla
Hypothalamus
Pituitary gland
Sympathetic ganglia
Adrenal cortex
Adrenal Medulla

7. The Adrenal Cortex
The adrenal cortex releases chemicals called corticosteriods.
These have a number of functions including releasing stored glucose and controlling swelling after injury.
Hypothalamus
Pituitary gland
Sympathetic ganglia
Adrenal cortex
Adrenal Medulla

8. The Adrenal Medulla The adrenal medulla releases adrenaline.
This hormone stimulates the sympathetic ganglia, keeping their activity at a high level.
Hypothalamus
Pituitary gland
Sympathetic ganglia
Adrenal cortex
Adrenal Medulla

9. Fight or Flight Response
Increase
oxygen intake
Release stored
glucose
Divert resources
away from
digestion
Ready to expend energy,
either by fighting or by running away

10. The Fight or Flight Response
An early evolutionary adaptation that is useful in dealing with physical threats
Helps us deal with short-term problems that can be solved by fighting or running
Unfortunately, many of the threats we face in our society do not fall into these categories…