The body's physiological response to severe stress over time. There are three stages, which consist of ALARM, RESISTANCE, and EXHAUSTION.
1 )Alarm stage sympathetic nervous system is activated, releasing cortisol, epinephrine, and norepinephrine 2) Resistance stage the organism begins to adapt to the stressor. the outward appearance seems normal, but inside the body is still reacting 3)Exhaustion stage the organism begins to be depleted and begins to break down due to chronic exposure of stressors. can lead to heart damage and increases in susceptibility of the immune system
This adaptive system towards stress, putting the body into flight-or-fight was helpful in the olden days, when our ancestors had to outrun predators quickly and deal with short term stress. However, this system our body has towards stress is ineffective towards long-term stress, and can be extremely detrimental.
SAM System (Sympatho-adreno-medullary)
Body's initial, rapid-acting stress response, involving the sympathetic nervous system and the adrenal medulla; also called the sympatho-adreno-medullary (SAM) system.
The system starts the ALARM stage of the General Adaption Syndrome. Stressors activate a process where the hypothalamus begins by activating the sympathetic nervous system, which stimulates the medulla of the adrenal glands. The adrenals release catecholamines, like norepinephrine and epinephrine, which activate the body's flight-or-fight response.
HPA System (Hypothalamic-Pituitary-Adrenocortical System)
The body's delayed stress response; involving the hypothalamus, pituitary, and adrenal cortex; also called the hypothalamic-pituitary-adrenocortical system (HPA).
The hypothalamus send signals to the pituitary gland, which stimulates the cortex of the adrenal glands to secrete CORTICOSTEROIDS. These hormones, especially CORTISOL, one of the CORTICOSTEROIDS, activate the body's energy supplies and help fight inflammation,
Once the cortisol levels reach a certain levels, parts of the brain, especially the HIPPCAMPUS tell the HYPOTHALAMUS to turn on the stress response. This is called a FEEDBACK loop. However, chronic stress can cause too high levels of cortisol, whereas not enough can cause too little levels of cortisol.
Moreover, this process lasts longer and helps the body return to homeostasis (the brain turns off the stress response,)
SAM System Process
1) Hypothalamus stimulates the medulla of the adrenal glands
2) the adrenals release catecholamines
3)Catecholamines like epinephrine and noepinephrine cause fight or flight response which include increased heart rate, blood pressure, respiration, muscle tension; decreased digestion, and constricted blood vessels
HPA System Process
1) The hypothalamus stimulate the pituitary glands 2) The pituitary glands activate the cortex (outer part) of the adrenal glands 3) The adrenal glands in response secret corticosteroids (cortisol) 4) Cortisol INCREASES blood sugar and metabolism (increased energy) 5) When coritsol reaches a certain level, certain parts of the brain, especially the hippocampus send messages to the hypothalamus to turn off the stress response. This is a normal feedback loop.
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