Stress and Stress Response (The Fight or Flight Response) скачать в хорошем качестве

Stress and Stress Response (The Fight or Flight Response)

Stress and Stress response Psychologist Richard Lazarus proposed that our initial perception of the event is more important in determining its impact that the event itself. You can think of many types or events or stressors. One category is related to having a significant personal life event (like divorce; death of a loved one, job loss, moving and so forth). Another category is experiencing a major traumatic event (like being victimized by an act of violence, being in a war zone; living through natural disaster like tournedos). Then there are the daily hassles and daily irritants (like interpersonal conflicts, misplacing or losing things, concerns about health, concerns about safety, micro-aggressions you may encounter, and the like). These daily hassles, because of their frequency, tend to be highly taxing in terms of the ongoing cost to our well being. There are also global/environmental stressors that affect all, but not individual like noise, crowdedness, smoke, etc. The concept of the stress response is related to a term- called Homeostasis which was introduced in early 1900s by an American physiologist Walter Cannon. Homeostasis describes how the body tries to maintain stability and internal balance in the face of any change like changes in the body temperature. Multiple systems in the body, including the nervous system and the endocrine system, work to help with orchestrating a fight or flight response or a stress response. For the central nervous system we have the brain with many internal structures that contribute to the fight or flight stress response. The adrenal glands each has two parts. One is the adrenal medulla, which is the insider part of the adrenal gland. This part (the adrenal medulla) releases catecholamines- epinephrine and norepinephrine. Sometimes called adrenaline and noradrenaline. Epinephrine is the one that more functionally important here. It helps in communicating to other parts of the body like the heart to increase heart rate and to the vessels to increase blood pressure. These are functions that support the sympathetic nervous system response to the threat or the stressor. In the outside layer of the adrenal gland is another part called the adrenal cortex. From here comes a stress hormones called cortisol. Cortisol is so important to many functions in the body since it affects just about all tissues including the brain. Cortisol release is not directly linked to the sympathetic nervous system, although they work together. Cortisol is part of another stress response system called the hypothalamic-pituitary-adrenocortical axis. This axis includes three structures. The hypothalamus, the pituitary gland, and the adrenal gland. The hypothalamus is a structure located in the brain – it releases a hormone called cortico-tropin relasing hormone (CRH). CRH is is transported to the pituitary glad also in the brain and there it stimulates the pituitary to release a hormone called adrenocorticotropic hormone (ACTH). ACTH moves through the blood circulation and reaches the adrenal gland (on the top of the kidneys), particularly the cortical part of that gland – the adrenal cortex There ACTH causes the release of the hormone cortisol. Cortisol provides feedback to the brain to slow down the release of ACTH and CRH – we call this negative feedback. This is important to keep things from going out of control. There is also a relatively a more recent evolution of the concept of h homeostasis and that allostasis introduced by neuroendocrinology’s Bruce McEwen. This concept reflects the active process of maintaining homeostasis and the cost of this process on the body. This is an important term to consider when thinking about the effects of stress on health