Answer
The body's response to stress produces the general adaption syndrome (GAS of Hans Selye). This may manifest in three stages: the flight or fight response, the resistance response, and exhaustion. When acute stress is present, the acute response is triggered by neural signals from the hypothalamus; these signals which involves the sympathetic nervous system mobilize of the body's resources for action. The purpose of this mobilization is to make increased levels of glucose and oxygen available for organs that need them most -- brain , heart, and skeletal muscles. The flight-or-fight response is brief (20-40 mins). If resistance to a persisent stressor must be maintained the resistance response kicks in. This second stage is initiated by hypothalamic releasing hormones --CRH, GHRH and TRH. These releasing hormones cause secretion/release of trophic hormones; ACTH, TSH and hGH from the anterior pituitary (AP). The tropic hormones promote the production of cortisol from the adrenal cortex, and thyroid hormone from the thyroid gland. The lipolysis and gluconeogenesis promoted by these hormones make more glucose available for synthesis of ATP. This provides the energy that allows the organism to continue resistance to the stress. If the body cannot sustain the resistant, to prolonged, unremitting stress, the third stage of the GAS, exhaustion, may supervene. In this stage there may be muscle wasting, GI ulceration, failure of pancreas beta cells, migraine headaches, anxiety, depression , and skin infections.
Work Step by Step
Stress my stimulate, or dysregulate both innate and adaptive immune responses. One link between the stress response and the immune response is the hormone interleukin-!. This hormone is secreted by macrophages which increase in number and motility in response to stress. Interleukin-1 stimulates the secretion of ACTH, and ACTH stimulates the secretion of cortisol. Cortisol is an anti-inflammatory , hormone that resists stress. But cortisol also has a negative feedback action on IL-1 secretion. In this way the stress response can turn off the immune response
