Stress And Learning : How Stress Affects The Brain Essay

The brain develops in such a way that it leaves itself vulnerable to these negative influences. The prenatal brain develops an overabundance of neurons, some of which are then carefully eliminated before age 4 (5). In a process similar to this, the amount of synapses between neurons is built up during early childhood and then pruned back for the next 30 years of life (5). These two processes are both disturbed by elevated levels of stress hormones (5). The two centers of the brain with the most postnatal changes, including the growth of new neurons after birth, are the hippocampus, which is part of the limbic system, and the cerebellar vermis (6). The hippocampus is in charge of creating and retrieving memories, working together with the other parts of the limbic system, such as the amygdala, which records the emotions for each memory. The vermis controls the production and release of two of the catecholamine neurotransmitters, dopamine and norepinephrine (6). Both the vermis and the limbic system have higher concentrations of receptors for the stress hormone cortisol than anywhere else in the brain (6). Due to this fact, these still-developing areas are the most vulnerable to the damage done by elevated levels of stress hormones.

When the body is in an unstable state or feels threatened, the body will set itself in a “fight or-flight-or-freeze” mode, also known as the stress response (Smith, R. Segal, and J. Segal). Another definition of stress, according to Firdaus Dhabhar, is that stress is “a constellation of events that begins with a stimulus or challenge that is detected by the brain that then activates the flight-or-flight systems in the body (biological stress response)” (Richter). Psychologist Connie Lillas presents a driving analogy in order to show the three most general ways people respond to stress. The first way is known as “foot on the gas.” This is the “fight” response, and a person is usually uptight and angry.

The stress of feeling afraid and anxious causes the body to release cortisol (a steroid hormone). This continuous release of cortisol may damage the amygdala; thus, causing the absence of neurons once the child becomes an adult. For this reason, early diagnosis and intervention is essential.

“When this response is chronically activated, people can suffer from decreased immunity and other health problems” (Good). Many other health problems can also occur when people have fight or flight constantly. Those who suffer from Post Traumatic Stress Disorder (PTSD) constantly live with the feeling of fight or flight. This can affect how they see normal stress throughout their day. Professionals work with people's mental health trying to allow them a harder trigger into the panic of a stressful situation, so get prescribed medical drugs to remain calm. The hypothalamus is a bit like a command center that controls the brain. It allows the brain to send signals through the nervous system throughout the body.Researcher at Harvard states, “While the amygdala sends a distress signal which can happen during work sudden deadline, or a persistent worry about losing a job can cause a mental shut down in the normal functions” (Harvard). it is most commonly found in humans, but humans are not the only things to use the fight or flight technique, animals and plants also take advantage of this

Dr. McEwen explains what happens to the brain when it is on stress, “The brain perceives and determines what is threatening as well as the behavioral and physiological responses to the stressor, which not only promote adaptation (“allostasis”) but also contribute to pathophysiology (“allostatic load/overload”) when those responses are overused and dysregulated.” (McEwen,1)

Chronic Stress affects the whole body, and especially the brain. In the brain, there is a balance of hormones, and the two stress related hormones are Epinephrine (Adrenaline) and Cortisol. Epinephrine is a hormone that is released quickly and dissipates quickly. However, Cortisol stays, and when you have too much of this stress hormone, it can cause diseases such as Osteoporosis and Heart disease. It also causes weight gain and mood swings. This increase in Cortisol actually causes brain cells to die, due to assisting in creating “free radicals”, which are unattached oxygen molecules, that punctures the brain cell walls, killing brain cells. Even though brain cells are created daily, Cortisol stops and slows the production of proteins (Brain-derived neurotrophic factor) that keep brain cells healthy and

The amygdala is made up of a group of nuclei located in the medial temporal lobe of the brain. (Mannironi, et al., 2013) The amygdala is believed to be key in stress response integration with its extensive network of efferent outcrops to other regions of the brain. (Mannironi, et al., 2013) Stress mediators such as adrenaline, cortisol, and corticotrophin releasing hormone, contribute to neuronal operative change and plasticity that are instrumental contributory to the stress response. (Mannironi, et al., 2013) Acute psychological stress creates a instant surge of hormone release, neuronal activation, and neurotransmission. (Mannironi, et al., 2013) This activation has an intense effect on the brain, leading to structural modification in the synaptic connectivity and dendritic spine morphology. (Mannironi, et al., 2013)

Cortisol has a main function, this is to restore homeostasis following exposure to stress (Randall’12, 2011), the effects of cortisol are felt over the entire body and “impact several homeostatic mechanisms. While cortisol’s primary targets are metabolic, it also affects ion transport, the immune response, and even memory” (Randall’12, 2011). Stress even over relatively short periods and in different contexts, “tend to produce similar results: prolonged healing times, reduction in ability to cope with vaccinations, and heightened vulnerability to viral infection. The long-term effects of constant cortisol exposure associated with chronic stress produces further symptoms, including impaired cognition, decreased thyroid function, and accumulation

Long-term alterations in the secretion include a glutocorticoid hormones cortisol via the hypothalamus pituitary adrenal access personal play crucial role in mediating the link between chronic stress exposure and ability to variety of diseases. (Stalder et al. 2012) Some of the biological consequences of such arousal were first identified by Selye (1956) as the General Adaptation Syndrome. Selye noted t h a t a principal characteristic of this response is an elevation in cortisol level. As a result of this early work and of more recent laboratory-based research, cortisol is now often regarded a s a "stress hormone" and as an objective marker of stress (Baum et al., 1982). (Pollard 1995)Registering for stressors cognitive affective states

Dr. Matthew Tull, a researcher for anxiety disorders, writes, "When we experience stress, the body releases a hormone called cortisol, which is helpful in mobilizing the body to respond to a stressful event.  Some animal studies, though, show that high levels of cortisol may damage or destroy cells in the hippocampus" (2016). As a result of the cortisol damaging the hippocampus, the hippocampus becomes smaller (Tull, 2016).

Fear is a survival mechanism. Our brains are able to detect when there is a source of stress that might be a threat, it then activates a series of events that enable us to be ready to fight or escape. This reaction is scientifically known as “fight or flight.” When stress activates that part of the brain, known as amygdala region, it overrides conscious thought which allows the brain to contribute all of its energy into facing the threat.

Cortisol is a steroid hormone, found in the glucocorticoids (GC) class of hormones. It controls many physiological processes, vital for the survival of humans. This includes “metabolism, immune response, cardiovascular activity, and brain function” (Chung et al. 2011). Over and above control functions, cortisol also helps regulate blood pressure and its use of proteins, carbohydrates, and fats. There is a strong correlation between stressful situations and circulating cortisol levels. The body response to stressful physiological or psychological situations by increasing the amount of cortisol secreted. This secretion causes the breakdown of muscle protein, which leads to the release of amino acids into the bloodstream. These

Stress is commonly known to have damaging effects on our bodies. One might argue that we exhibit feelings of depression, anxiety, social discomfort, fatigue, weight changes and other undesirable symptoms. However, the most crucial consequence of long-term stress is brain damage. Long-term exposure to glucocorticoids results in deterioration of neurons that are located in the hippocampus (Carlson, 2013). The hippocampus hosts the formation for learning and memory. When this area is damaged due to exposure to long-term stress, memory and learning can be impaired. Impaired hippocampal neurogenesis is also an essential role player in cases of depression (Thomas, Hotsenpiller & Peterson, 2007; Carlson, 2013). Jensen, Genefke and Hyldebrandt (1982)

Situations interpreted as being potentially dangerous, the body release hormones that respond to that stress stimuli. It is the body’s method of reaction to a challenge. A common stress hormone, released by the body, is cortisol which affects the metabolic system. An example of a stressful situation is when a student begins to write a four-page paper and the individual’s mind draws a blank and worries when the deadline near approaches. According to C. Bergland, stress is perceived as either negative or positive that can have an impact on a person 's mental and physical well-being (Bergland, 2013). Stress is something that every person endures in his or her life and is a difficult factor to control. Many people understand the symptoms and reasons for a stress response but are unaware of the biological physiology process to better control the symtoms. This paper will focus on the hormone, cortisol, and its background, cellular physiology, function, effects, and understood disorders associated with it.

As illustrated in Figure 2, pCRH stimulates ACTH release in the fetus which signals the adrenal glands to release cortisol. Rather than inhibit pCRH through negative feedback as seen in Figure 1, cortisol stimulates production of pCRH. This can have lasting effect on the fetus. Throughout a woman’s pregnancy levels of CRH and cortisol increase which can be exacerbated due to chronic stress. As we discussed in our lectures, the hippocampus and hypothalamus have an abundance of reports for CRH and glucocorticoids. Elevated levels of CRH in the womb has been linked to learning and memory problems. In one human study, fetus exposed to high amounts of CRH were unable to differentiate between repeated tones and new different tones. (Stressed-out, or in (utero)?) This indicates that the high levels of CRH and cortisol can impair the part of the brain designated for learning and