biological models of stress

stressor

a stimulus (person, situation or event) which activates (prompts) the stress response.

internal stressor

a stimulus from within a person's body that prompts the stress response

external stressor

a stimulus from outside of a person's body that prompts the stress response

stress

a psychological and physiological experience that occurs when an individual encounters something of significance that demands their attention and/or efforts to cope

Fight-flight-freeze response

an involuntary, physical response to a sudden and immediate threat in readiness to deal with stressor:

fight

confront and fight off the threat (sympathetic NS fires only)

flight

escaping by running to safety (sympathetic NS fires only)

freeze

keeping absolutely still and silent (sympathetic NS and parasympathetic NS fir simultaneously - parasympathetic dominant first)

acute stress/stressor

a form of stress/stressor produces high level arousal for a short period.

SAM as response to an acute stressor

Response: fight or flight - sympathetic adreno-medullary system activated.

hypothalamus --> sympathetic nervous system --> adrenal medulla (located in adrenal glands just above the kidneys) --> release of adrenaline and noradrenaline

Result of SAM response:

Increased quick, automatic, energy and heightened arousal that cannot be sustained

chronic stress/stressor

a form of stress/stressor that endures for several months or longer

HPA Axis as response to a chronic stressor

Response: HPA Axis activated

hypothalamus --> pituitary gland releases --> adrenocorticotropic hormone (ACTH) activates --> adrenal cortex releases --> cortisol

cortisol

a hormone that is released in times of stress to aid the body in initiating and maintaining heightened arousal