Stress and the Brain

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response to the cortex with signals that are either excited or not excited which makes a big difference in the way feeling and processes are absorbed. When the RAS is not excited easily this results in difficult learning, poor memory, and little self-control. On the other end of the RAS, when the RAS are overly excited we see responses such as being easily startled, hypervigilance, restlessness, and hyperactivity. When the RAS is has normal levels the brain functions as it should. With the reticula activating system it is connected with the limbic system and messages are passed to the limbic system and the thalamus. The limbic system is the filtering for the incoming messages and then the hypothalamus plays in a role.

The hypothalamus now plays a part in the stressor with two major pathways: the endocrine system and the autonomic nervous system. The stressor activates the hypothalamus to release and secrete hormones from the brain to help with a response. Some of the hormones release from the brain to help with stressors and other function in the body are: corticotropin releasing factor (CRF) that releases adrenocorticotropic hormone (ACTH), thyrotropic hormone releasing factor (TRF) stimulated in the pituitary gland to secrete thyrotropic hormone (TTH) which stimulates the thyroid gland to secrete thyroxin. The anterior hypothalamus also stimulates the pituitary gland to secrete oxytocin and vasopressin (ADH). The hippocampus is the part of the brain that “sounds the alarm” when stress is present. Glucocorticoids are then released by the adrenal glands and is noticed by receptors in the hippocampus. If stress is drawn out over the years it damages brain cells that are not reversible, so these cells are lost forever. With the stress we encounter are not completely understood but it means we do not respond well to stressors and having limited glucocorticoid receptors.