Stress, a word usually associated with experiences that are challenging both emotionally and physiologically, is an internal or external signal alluding to potential threats. Understanding stress is of utmost importance as it is important biologically, enabling adaptive processes to one’s ever-changing environment (Gunnar & Quevedo, 2007). Animal stress responses are composed of the activation of neurobiological systems that help preserve viability through allostasis, an active process by which the body responds to daily events and maintains a state of equilibrium (McEwen, 2007).
There are two systems in which the stress responses of mammals are affected: the sympathetic-adrenomedullary system (SAM) and the hypothalamic-pituitary-adrenocortical system (HPA axis). The SAM is part of the system which releases adrenaline/epinephrine from the center of the adrenal gland. These increases in the circulation of epinephrine enable rapid mobilization of metabolic resources and organization of the fight or flight response. In contrast, the production of glucocorticoids by the HPA axis takes time and is able to pass through the blood brain barrier (Gunnar & Quevedo, 2007; McEwen, 2007). But what is the method behind the HPA axis?
The anatomical structures known to mediate the stress response are found within both the central nervous system and peripheral tissues. If one were to take a deeper look into the HPA axis, it would be clear that the effectors of this stress response are localized within the paraventricular nucleus of the hypothalamus (PVN), the anterior lobe of the pituitary gland, and adrenal glands. Neurons localized in the PVN synthesize corticotropin releasing factor (CRF) and vasopressin. CRF, a key neuropeptide, has been im...
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...stress. Journal of Psychosomatic Research, 53(4), 865-871.
Vyas, A., Mitra, R., Shankaranarayana Rao, B. S., & Chattarji, S. (2002). Chronic stress induces contrasting patterns of dendritic remodeling in hippocampal and amygdaloid neurons. Neuroscience, 22(15), 6810-8.
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Adrenaline and glucocorticoids are critical to survival. Animals’ stress responses turn off after escaping from life-threatening situations. However, humans’ stress response come from a psychological state of fear or threat. We are often stressed out due to traffic, increasing taxes, instead of actual life-or-death situations. What’s worse, we are stressed constantly. Since we cannot
The hypothalamus in the brain is above the pituitary gland. The hypothalamus releases corticotrophin (CHR) which is a chemical messenger. CHR stimulates the pituitary gland to release adrenal corticotrophin (ACTH). ACTH which is released into the blood then signals the adrenal gland. When the adrenal gland receives ACTH it is the chemical signal for cortisol production. In a normal system cortisol (an anti-inflammatory) production would st...
McEwen, B. S., & Gianaros, P. J. (2011). Stress-and allostasis-induced brain plasticity. Annual review of medicine, 62, 431-445.
The amygdala is where all the information is gathered from all our senses. It requests all the stress hormones to be released from the hippocampus or the hypothalamus, the pituitary and the adrenal glands. This gets the body ready for either flight, freeze or fight mode (Rosenthal, 2015). These glands releases noradrenaline, epinephrine, cortisone and glucose which gets pumped into your limbs making you ready to fight or run away from the situation (Seahorn, 2016). The increase in stress hormones interferes with the body to regulate itself and the nervous systems remains highly activated leading to the body being fatigue (Rosenthal, 2015).
When a receptor is activated and the stimulus is taken to the hypothalamus and then relayed out to the “limbic system and neocortical areas…impulses stimulate the neuroendocrine and autonomic nervous system,” which can cause an array of issues if not careful and if the stress signal is prolonged. (3)
Each bodily physiological system has an individual established set point, or level of balance; however, some fluctuations in these levels are tolerated. The balance of any system can be, and regularly is disturbed by internal and/or external events of the mechanical, physical, chemical, biological, and/or social types. When this balance is disrupted, and involuntary mobilizations of biological processes are not able to re-establish it, an alarm reaction is activated (Schedlowski and Tewes, 1999). This reaction is referred to as a stress response, and the activating agent is the stressor (Selye, 1936).
Research has also shown that extreme stress has a deleterious effect on the frontal lobe and is associated with the production of false memories.
From the time of conception, a child’s brain begins to develop and the nurturing or neglectful experiences that parents provide the child can dramatically influence his or her neurological development. As Farah et al. (2008) and Lupien et al. (2000) found, a high stress environment often leads to the develop...
McEwen, B. (1999). Stress and hippocampal plasticity. (Vol. 22, pp. 105-122). New York,NY: Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, The Rockefeller University. Retrieved from http://www.annualreviews.org/doi/abs/10.1146/annurev.neuro.22.1.105
Talge, N. M., Neal, C., & Glover, V. (2007). Antenatal maternal stress and long-term effects on child neurodevelopment: how and why?. Journal of Child Psychology and Psychiatry, 48(3/4), 245-261.
To a great extent, stress can be a helpful response, especially for prehistoric humans. During this era, our species needed to react quickly to outside stimuli through a response of “fight or flight”. Through stress, certain hormones are released to help the individual resist the stressor, which may have meant running away from a natural predator. Thus, stress is a positive response that ensures the survival of the species. However, stress over a prolonged period of time causes exhaustion in the individual. Consequently, although stress can be helpful for individuals today, many often experience chronic stress, inflicting varying degrees of damage to their bodies.
LaPlante, Charil A., DP, C. Vaillancourt, and S. King. "Prenatal Stress and Brain Development." NCBI. U.S. National Library of Medicine, 05 Oct. 2010. Web. 03 Nov. 2013.
Kumar, Anil, Puneet Rinwa, Gurleen Kaur, and Lalit Machawal. "Stress: Neurobiology, consequences, and management." Journal of Pharmacy and Bioallied Sciences, 2013: 1-7.
The term “stress” has multiple meanings. As Richard Lazarus stated in his 1966 book “Psycho...
First, stress is defined as an unpleasant state of emotional and physiological arousal that people experience in situations that they perceive as dangerous or threatening to their well being (Patel, 14). Stress is a universal feeling to everyone but the word stress means different things to different people. Some people define stress as events or situations that cause them to feel tension, pressure or negative emotions such as anxiety or anger (Patel, 15). Other people may view stress as a process involving a person’s interpretation and response to a threatening event. In any case, stress has many facets of how one perceives and responds to the certain predicament that is ailing them.