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.

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

Physiological Stress Response Hypothalamus Pituitary gland Adrenal cortex Adrenal Medulla 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 Sympathetic ganglia Finish

The Hypothalamus Hypothalamus Pituitary gland Adrenal cortex Adrenal Medulla 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.pituitary gland sympathetic ganglia Sympathetic ganglia Finish

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

The Sympathetic Ganglia Hypothalamus Pituitary gland Adrenal cortex Adrenal Medulla 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 medullaadrenal medulla Sympathetic ganglia Finish

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

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

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

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…