Stressijärjestelmä

Stressijärjestelmä refers to the complex biological system in organisms that responds to stressors. It encompasses neurological, endocrine, and immune components that work together to maintain homeostasis when faced with challenges. The primary components include the sympathetic nervous system and the hypothalamic-pituitary-adrenal (HPA) axis.

When a stressor is perceived, the sympathetic nervous system is rapidly activated, leading to the "fight-or-flight" response. This involves the release of adrenaline and noradrenaline, which increase heart rate, blood pressure, and glucose levels, preparing the body for immediate action. Simultaneously, the HPA axis is engaged. The hypothalamus releases corticotropin-releasing hormone (CRH), which stimulates the pituitary gland to release adrenocorticotropic hormone (ACTH). ACTH then signals the adrenal glands to produce cortisol, a steroid hormone that helps regulate metabolism and suppresses inflammation.

While acute stress responses are crucial for survival, chronic activation of the stressijärjestelmä can have detrimental effects on health. Prolonged exposure to stress hormones can lead to a range of issues, including cardiovascular problems, weakened immune function, mental health disorders like anxiety and depression, and metabolic disturbances. Understanding the intricacies of the stressijärjestelmä is vital for both understanding physiological responses to adversity and for developing strategies to mitigate the negative consequences of chronic stress.