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Physiological responses to stress
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HPA Axis
The HPA axis has been receiving a lot of attention in recent studies. The studies are looking at potential pre-natal and post-natal roles it plays in schizophrenia. When the body becomes under stress, the hypothalamic-pituitary-adrenal axis (HPA) is used by the hypothalamus to mediate cortisol output (Walker, 2002). For pre- and post-natal development, the HPA axis is an important stress defense (Zhang et al., 2014). The HPA axis releases corticotropin-releasing factor (CRF), adrenocorticotropic hormone (ACTH) and glucocorticoids (GC) (Misiak et al., 2014). Glucocorticoids, like cortisol, are stress hormones and function multiple ways which include the inhibition of inflammatory response and also has an influence on cognitive functioning
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Fetal exposure to prenatal stress is capable of reprograming the HPA axis to have an increased responsiveness to glucocorticoids later in life as well as inhibit the secretion of glucocorticoids due to stress (Koenig, Kirkpatrick and Lee, 2002).
The Immune system and Inflammatory Response
The immune system is composed of two parts, the innate and acquired, which respond to antigens present in the body. The innate side is the first line of defense against antigens and matures in the thymus. An antigen that produces an immune response are called immunogens (Delves and Roitt, 2000). A mechanism used in defense by the innate side is inflammation, cytokines in this process that are pro-inflammatory include IL-1ß, IL-6 and tumor necrosis factor (TNF)-alpha (Meyer, 2013). The acquired side is slower in response and matures in the bone marrow. Both cells start in the bone marrow, but T-cells migrate to the thymus, as thymocytes, at an early stage to finish maturation; if the thymocytes do no complete their journey to the thymus they die by performing apoptosis (Parkin and Cohen,
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The research that is out there does implicate immune system dysfunction in prenatal immune activation as a role in the development of schizophrenia. More research needs to be conducted on looking at the effects of cytokines on the neurodevelopmental processes in humans. There are multiple animal studies that have found neurodevelopmental effects of cytokines on the offspring due to prenatal immune activation (Meyer et al., 2005; Meyer 2013; Patterson 2009; Deverman and Patterson, 2009). The found effects have implications on cytokines on the neurodevelopmental processes in humans. Stress research has shown the decreased effectiveness of the prenatal enzyme 11ß-HSD2 which protects the developing fetus from maternal factors (O'Donnell, O'Connor and Glover, 2009). Future studies are needed to look at what other possible placenta enzymes are down regulated and if that allows other cytokines to cross. More studies like the one conducted by Ellman et al. (2010) needs to be done looking at individual cytokine effects during maternal presentation. The data discussed in the paper supports that prenatal immune activation is linked with structural and functional abnormalities of the neurodevelopment of the fetus's brain. The key factors suggested are the timing, dosage and type of cytokine.
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 immune system is made up of a network of cells, tissues, and organs that work together to protect the body, and it defends the body from “foreign invaders.” Immunity can be divided in two three different defenses, and these are defined as first, second and third lines of defense. The first line of defense for the immune system is the primary defense against pathogens entering the body from the surface in order to prevent the start of disease and infection. Some examples of the first line of defense is the skin, protecting the external boundaries of the body, and the mucous membranes, protecting the internal boundaries of the body. Although the skin and mucous membranes work on the internal and external boundaries, they both release chemicals
The neurodevelopmental Basis of Schizophrenia. Austin, TX: Landes Co.
Each part of the immune system plays a certain role in keeping pathogens out of the body. Bone marrow is the soft material found inside bones. It is used to make the lymphocytes needed in the body every day. Located above the heart, the thymus is a gland that helps produce a special kind of lymphocyte.
Cortisol is in the class of hormones called glucocorticoids and affects almost every organ in the body. One of the most important functions of cortisol is to help regulate the body’s response to stress. Cortisol is also responsible for other necessary functions including: helping to maintain blood pressure and cardiovascular functions, helping to slow the immune system’s inflammatory response, helping to balance the effects of insulin in breaking down sugars for energy, helping to regulate the metabolism of proteins, carbohydrates, and fats, and helping to maintain proper arousal of sense of well being. The amount of cortisol is precisely balanced and regulated by the brain’s hypothalamus.
Schizophrenia is one of the most misdiagnosed illnesses of all time. Its characteristics of identification – hallucinations, delusions, lack of body control, etc. - often cause it to be identified as depression or post-traumatic stress disorder (PTSD). Doctors and scientists still debate the major cause of schizophrenia. Through research it is carefully observed that genetic factors play a larger role in the cause of schizophrenia than environmental factors.
Organisms have three types of immunity: innate. adaptive, and passive. Innate immunity is common among all organisms and reacts the same to all pathogenic infections. Innate immunity includes protective layers of the body, such as the skin and mucous membranes in the nose and throat. Adaptive immunity is the second type of immunity. Adaptive immunity develops throughout an organism’s life. An example of this is the lymphocytes, which develop when an organism is exposed to diseases or through vaccination (with some exceptions). Passive immunity is borrowed from another source and lasts for a short period of time, for example, antibodies in a woman's breast milk, which help prevent their young offspring from acquiring infections in their early years. An example of this in snakes is their tolerance to their own venom, which they are exposed to early in life which prevents them from dying if exposed later.
Each second of fetal development during pregnancy is of extreme importance. This period of prenatal development is a time of change and growth with many factors affecting all areas of growth. Different stimuli having long-lasting effects on development is a process known as programming. The goal of this first article, (put the name of the article here) is to look into the idea of programming and how the influence of stress effects prenatal development. It begins with a biological approach. Looking at the role of Glucocorticoids cortisol in fetal development, the article states that they play a critical role in development and are associated with the “hypothalamic-pituitary-adrenal (HPA) axis, one of the body’s major stress responsive systems.” (Davis & Sandman, 2010) This cortisol increases in mothers over the course of pregnancy and is important in brain development in the fetus. While these Glucocorticoids are important and essential to prenatal development, overexposure can lead to negative effects, including emotional disturbances in early childhood, deregulated stress responses in infa...
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.
According to the recent research from Biochemical theories states that schizophrenia is caused by neurotransmitter dopamine in the prefrontal cortex which is a chemical that transmits signals in the brain. On the other hand the researchers states that psychological factors is cognitive function such as learning, m...
National Library of Medicine, National Institute of Health. Schizophrenia. 31 Jan 2013. Web. 15 May 2014
There are many different genetic and environmental factors that contribute to the development of schizophrenia. Some environmental factors would include exposure to certain viruses, stress within that person’s life ( Parents of the person going through a divorce, trouble in school, etc.), prenatal malnutrition in pregnant women, and certain types of drug use in teens. These drugs, such as cannabis, methamphetamine, hash, and marijuana, could be a very likely cause of schizophrenia in teens. Alcohol has also been considered a very likely contribute to the disorder as well. Over all of that, the factors that contribute the most to the development of this disorder are complications during pregnancy. This can include having diabetes while the woman is pregnant, complications during the birth of the child, unusual growth of the fetus, low birth weight, and birth before the baby is fully developed. A pregnant woman can get a response to an infection by the placenta, the fetus, or even the woman herself. Having this infection can set off a certain toxic effect on the developing neurons within the baby, and it will regulate the neurodevelopment processes such as the ones found in schizophrenia.
When something foreign is produced into the body, our immune system automatically goes into overdrive. “Is this something I’ve encountered before or is this a new invader?” Our body must distinguish between the two. This is known as either a primary or secondary immune response. If this is initial contact with the foreign antigen, it is known as a primary immune response. Over a period of several days, the body begins to produce an adequate amount of antibody against the invading antigen. This is a non-specific line of defense because it is the first instance of contact with the antigen. The bone marrow produces T lymphs and B lymphs that play an important role in this primary immune response. T lymphs travel to the thymus while B lymphs
Adaptive immune system happens much quicker to the presence of an “infection creating potent mechanisms for neutralizing or eliminating the microbes. There are two types of adaptive immune responses: humeral immunity, mediated by antibodies produced by B lymphocytes, and cell-mediated immunity, mediated by T lymphocytes.”
Huizink, A. C., Robles de Medina, P. G., Mulder, E. J., Visser, G. H., & Buitelaar, J. K. (2003). Stress during pregnancy is associated with developmental outcome in infancy. Journal of Child Psychology and Psychiatry, 44(6), 810-818.