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«Medical university of Astana»

Department of normal physiology

SIW

Subject: Emotional stress

Performed by: Karipzhanova I.

Group: 228 GM

Checked by:

2013

Emotional stress

In recent years, the living condition is getting better than the past; people have better education life, better civilized living and better social life. As technology and the form of mass media has been changing so fast, people can have information easily through internet and chat with their friends and so on. Also, people are enjoying their life with exciting hobbies. Even though, life is more comfortable and better than before, more people have lots of stress.

When they wake up, they start the morning with their job or school, fight with their projects and spend the whole day working. This routine is performed every day, which causes too much stress, which causes sleeplessness, heart disease, depression and even death. However, there are the ways that people can minimize stress and manage the stress that is inevitable. Positive thinking is then used to create positive assertions that people can use to counter negative thoughts. These confirmations compensate for negative thoughts and build their self-confidence.

Stress

Stress is a person's response to a stressor such as an environmental condition or a stimulus. Stress is a body's method of reacting to a challenge. According to the stressful event, the body's way to respond to stress is by sympathetic nervous system activation which results in the fight-or-flight response. Stress typically describes a negative condition or a positive condition that can have an impact on a person's mental and physical well-being.

Types of a stress

Eustress

The concept has two values -- "a stress caused by positive emotions" and "the weak stress mobilizing an organism".

Distress

Negative type of a stress with which organism not in forces to cope. It undermines health of the person and can lead to a serious illness. The immune system suffers from a stress. In a stressful condition people more often appear infection victims as production of immune cages considerably falls in the period of a physical or mental stress.

Psychological stress

Psychological stress as the type of a stress, is understood by different authors differently, but many authors define it as a stress caused by social factors.

Stress and homeostasis

The term stress had none of its contemporary connotations before the 1920s. It is a form of the Middle English destresse, derived via Old French from the Latin stringere, "to draw tight." The word had long been in use in physics to refer to the internal distribution of a force exerted on a material body, resulting in strain. In the 1920s and 1930s biological and psychological circles occasionally used the term to refer to a mental strain or to a harmful environmental agent that could cause illness. Walter Cannon used it in 1926 to refer to external factors that disrupted what he called homeostasis. But Stress as an explanation of lived experience is absent from both lay and expert life narratives before the 1930s".

Homeostasis is a concept central to the idea of stress. In biology, most biochemical processes strive to maintain equilibrium, a steady state that exists more as an ideal and less as an achievable condition. Environmental factors, internal or external stimuli, continually disrupt homeostasis; an organism's present condition is a state in constant flux moving about a homeostatic point that is that organism's optimal condition for living. Factors causing an organism's condition to diverge too far from homeostasis can be experienced as stress. A life-threatening situation such as a physical insult or prolonged starvation can greatly disrupt homeostasis. On the other hand, an organism's effortful attempt at restoring conditions back to or near homeostasis, often consuming energy and natural resources, can also be interpreted as stress. In such instances, an organism's fight-or-flight response recruits the body's energy stores and focuses attention to overcome the challenge at hand.

The ambiguity in defining this phenomenon was first recognized by Hans Selye (1907-1982) in 1926. In 1951 a commentator loosely summarized Selye's view of stress as something that "…in addition to being itself, was also the cause of itself, and the result of itself." First to use the term in a biological context, Selye continued to define stress as "the non-specific response of the body to any demand placed upon it". As of 2011 neuroscientists such as Bruce McEwen and Jaap Koolhaas believe that stress, based on years of empirical research, "should be restricted to conditions where an environmental demand exceeds the natural regulatory capacity of an organism". Despite the numerous definitions given to stress, homeostasis appears to lie at its core.

Stress can have profound effects on human biological systems. Biology primarily attempts to explain major concepts of stress using a stimulus-response paradigm, broadly comparable to how a psychobiological sensory system operates. The central nervous system (brain and spinal cord) plays a crucial role in the body's stress-related mechanisms. Whether one should interpret these mechanisms as the body's response to a stressor or embody the act of stress itself is part of the ambiguity in defining what exactly stress is. Nevertheless, the central nervous system works closely with the body's endocrine system to regulate these mechanisms. The sympathetic nervous system becomes primarily active during a stress response, regulating many of the body's physiological functions in ways that ought to make an organism more adaptive to its environment. Below there follows a brief biological background ofneuroanatomy and neurochemistry and how they relate to stress.

Neuroanatomy

The brain plays a critical role in the body's perception of and response to stress. However, pinpointing exactly which regions of the brain are responsible for particular aspects of a stress response is difficult and often unclear. Understanding that the brain works in more of a network-like fashion carrying information about a stressful situation across regions of the brain (from cortical sensory areas to more basal structures and vice versa) can help explain how stress and its negative consequences are heavily rooted in neural communication dysfunction. In spite of this, several important brain structures implicated in playing key roles in stress response pathways are described below.

The hypothalamus is a small portion of the brain located below the thalamus and above the brainstem. One of its most important functions is to help link together the body's nervous and endocrine systems. This structure has many bidirectional neural inputs and outputs from and to various other brain regions. These connections help regulate the hypothalamus' ability to secretehormones into the body's blood stream, having far-reaching and long-lasting effects on physiological processes such as metabolism. During a stress response, the hypothalamus secretes various hormones, namely corticotropin-releasing hormone, which stimulates the body's pituitary gland and initiates a heavily regulated stress response pathway.

The amygdala is a small, "almond"-shaped structure located bilaterally, deep within the medial temporal lobes of the brain and is a part of the brain's limbic system, with projections to and from the hypothalamus, hippocampus, and locus coeruleus, among other areas. Thought to play a role in the processing of emotions, the amygdala has been implicated in modulating stress response mechanisms, particularly when feelings of anxiety or fear are involved.

The hippocampus is a structure located bilaterally, deep within the medial temporal lobes of the brain, just below each amygdala, and is a part of the brain's limbic system. The hippocampus is thought to play an important role in memory formation. There are numerous connections to the hippocampus from the cerebral cortex, hypothalamus, and amygdala, among other regions. During stress, the hippocampus is particularly important, in that cognitive processes such as prior memories can have a great influence on enhancing, suppressing, or even independently generating a stress response. The hippocampus is also an area in the brain that is susceptible to damage brought upon by chronic stress.

The prefrontal cortex, located in the frontal lobe, is the anterior-most region of the cerebral cortex. An important function of the prefrontal cortex is to regulate cognitive processes including planning, attention, and problem solving through extensive connections with other brain regions. The prefrontal cortex can become impaired during the stress response.

The locus coeruleus is an area located in the pons of the brainstem that is the principal site of the synthesis of the neurotransmitter norepinephrine, which plays an important role in the sympathetic nervous system's fight-or-flight response to stress. This area receives input from the hypothalamus, amygdala, and raphe nucleus among other regions and projects widely across the brain as well as to the spinal cord.

The raphe nucleus is an area located in the pons of the brainstem that is the principal site of the synthesis of the neurotransmitter serotonin, which plays an important role in mood regulation, particularly when stress is associated with depression and anxiety. Projections extend from this region to widespread areas across the brain, namely the hypothalamus, and are thought to modulate an organism's circadian rhythm and sensation of pain among other processes.

The spinal cord plays a critical role in transferring stress response neural impulses from the brain to the rest of the body. In addition to the neuroendocrine blood hormone signaling system initiated by the hypothalamus, the spinal cord communicates with the rest of the body by innervating the peripheral nervous system. Certain nerves that belong to the sympathetic branch of the central nervous system exit the spinal cord and stimulate peripheral nerves, which in turn engage the body's major organs and muscles in a fight-or-flight manner.

The adrenal gland is a major organ of the endocrine system that is located directly on top of the kidneys and is chiefly responsible for the synthesis of stress hormones that are released into the blood stream during a stress response. Cortisol is the major stress hormone released by the adrenal gland.

In addition to the locus cerulean existing as a source of the neurotransmitter norepinephrine within the central nervous system, the adrenal gland can also release norepinephrine during a stress response into the body's blood stream, at which point norepinephrine acts as a hormone in the endocrine system.

Neurochemistry

Corticotropin-releasing hormone is the neurohormone secreted by the hypothalamus during a stress response that stimulates the anterior lobe of the pituitary gland by binding to its corticotropin-releasing hormone-receptors, causing the anterior pituitary to release adrenocorticotropic hormone.

Adrenocorticotropic hormone is the hormone secreted by the anterior lobe of the pituitary gland into the body's blood stream that stimulates the cortex of the adrenal gland by binding to its adrenocorticotropic hormone-receptors, causing the adrenal gland to release cortisol.

Cortisol

Cortisol is a steroid hormone, belonging to a broader class of steroids called glucocorticoids, produced by the adrenal gland and secreted during a stress response. Its primary function is to redistribute energy (glucose) to regions of the body that need it most (i.e., the brain and major muscles during a fight-or-flight situation). As a part of the body's fight-or-flight response, cortisol also acts to suppress the body's immune system.

Cortisol is synthesized from cholesterol in the adrenal cortex. Its primary function is to increase blood sugar through gluconeogenesis, suppress the immune system and aid in fat and protein metabolism.

Norepinephrine

Norepinephrine is a neurotransmitter released from locus coeruleus when stimulated by the hypothalamus during a stress response. Norepinephrine serves as the primary chemical messenger of the central nervous system's sympathetic branch that prepares the body for fight-or-flight response.

Serotonin

Serotonin is a neurotransmitter synthesized in the raphe nucleus of the pons of the brainstem and projects to most brain areas. Serotonin is thought to play an important role in mood regulation. Stress-induced serotonin dysfunctions have been associated with anxiety, fear, and depression-like symptoms.

Neuropeptide Y

Neuropeptide Y is a protein that is synthesized in the hypothalamus and acts as a chemical messenger in the brain. Traditionally, it has been thought to play an important role in appetite, feeding behavior, and satiety, but more recent findings have implicated Neuropeptide Y in anxiety and stress, specifically, stress resiliency.

Biological mechanisms

Hypothalamic-pituitary-adrenal (HPA) axis

Basic hypothalamic-pituitary-adrenal axis summary (corticotropin-releasing hormone=CRH, adrenocorticotropic hormone=ACTH).

The HPA axis is a multi-step biochemical pathway where information is transmitted from one area of the body to the next via chemical messengers. Each step in this pathway, as in many biochemical pathways, not only passes information along to stimulate the next region but also receives feedback from messengers produced later in the pathway to either enhance or suppress earlier steps in the pathway - this is one way a biochemical pathway can regulate itself, via a feedback mechanism.

When the hypothalamus receives signals from one of its many inputs (e.g., cerebral cortex, limbic system, visceral organs) about conditions that deviate from an ideal homeostatic state (e.g., alarming sensory stimulus, emotionally charged event, energy deficiency), this can be interpreted as the initiation step of the stress-responsecascade. The hypothalamus is stimulated by its inputs and then proceeds to secrete corticotropin-releasing hormones. This hormone is transported to its target, the pituitary gland, via the hypophyseal portal system (short blood vessels system), to which it binds and causes the pituitary gland to, in turn, secrete its own messenger, adrenocorticotropic hormone, systemically into the body's blood stream. When adrenocorticotropic hormone reaches and binds to its target, the adrenal gland, the adrenal gland in turn releases the final key messenger in the cascade, cortisol. Cortisol, once released, has widespread effects in the body. During an alarming situation in which a threat is detected and signaled to the hypothalamus from primary sensory and limbic structures, cortisol is one way the brain instructs the body to attempt to regain homeostasis - by redistributing energy (glucose) to areas of the body that need it most, that is, toward critical organs (the heart, the brain) and away from digestiveand reproductive organs, during a potentially harmful situation in an attempt to overcome the challenge at hand.

After enough cortisol has been secreted to best restore homeostasis and the body's stressor is no longer present or the threat is no longer perceived, the heightened levels of cortisol in the body's blood stream eventually circulate to the pituitary gland and hypothalamus to which cortisol can bind and inhibit, essentially turning off the HPA-axis' stress-response cascade via feedback inhibition. This prevents additional cortisol from being released. This is biologically identified as a normal, healthy stress mechanism in response to a situation or stressor - a biological coping mechanism for a threat to homeostasis.

It is when the body's HPA-axis cannot overcome a challenge and/or is chronically exposed to a threat that this system becomes overtaxed and can be harmful to the body and brain. A second major effect of cortisol is to suppress the body's immune system during a stressful situation, again, for the purpose of redistributing metabolic resources primarily to fight-or-flight organs. While not a major risk to the body if only for a short period of time, if under chronic stress, the body becomes exceptionally vulnerable to immune system attacks. This is a biologically negative consequence of an exposure to a severe stressor and can be interpreted as stress in and of itself - a detrimental inability of biological mechanisms to effectively adapt to changes in homeostasis.

Immune response

Cortisol can weaken the activity of the immune system. Cortisol prevents proliferation of T-cells by rendering the interleukin-2 producer T-cells unresponsive to interleukin-1 (IL-1), and unable to produce the T-cell growth factor.[35]Cortisol also has a negative-feedback effect on interleukin-1.[36] IL-1 must be especially useful in combating some diseases; however, endotoxic bacteria have gained an advantage by forcing the hypothalamus to increase cortisol levels (forcing the secretion of CRH hormone, thus antagonizing IL-1). The suppressor cells are not affected by glucosteroid response-modifying factor (GRMF),[37] so the effective setpoint for the immune cells may be even higher than the setpoint for physiological processes (reflecting leukocyte redistribution to lymph nodes, bone marrow, and skin). Rapid administration of corticosterone (the endogenous Type I and Type II receptor agonist) orRU28362 (a specific Type II receptor agonist) to adrenalectomized animals induced changes in leukocytedistribution. Natural killer cells are not affected by cortisol.

Effect of stress on the immune system

Stress is the body's reaction to any stimuli that disturb its equilibrium. When the equilibrium of various hormones is altered the effect of these changes can be detrimental to the immune system. Much research has shown a negative effect stress has on the immune system, mostly through studies where participants were subjected to a variety of viruses. In one study, individuals caring for a spouse with dementia, representing the stress group, saw a significant decrease in immune response when given an influenza-virus vaccine compared to a non-stressed control group. A similar study was conducted using a respiratory virus. Participants were infected with the virus and given a stress index. Results showed that an increase in score on the stress index correlated with greater severity of cold symptoms. Studies with HIV have also shown stress to speed up viral progression. Men with HIV were 2-3 times more likely to develop AIDS when under above average stress.

Effects of chronic stress

Chronic stress is defined as a "state of prolonged tension from internal or external stressors, which may cause various physical manifestations - e.g., asthma, back pain, arrhythmias, fatigue, headaches, HTN, irritable bowel syndrome, ulcers, and suppress the immune system". Chronic stress takes a more significant toll on your body than acute stress does. It can raise blood pressure, increase the risk of heart attack and stroke, increase vulnerability to anxiety and depression, contribute to infertility, and hasten the aging process. For example, results of one study demonstrated that individuals who reported relationship conflict lasting one month or longer have a greater risk of developing illness and show slower wound healing. Similarly, the effects that acute stressors have on the immune system may be increased when there is perceived stress and/or anxiety due to other events. For example, students who are taking exams show weaker immune responses if they also report stress due to daily hassles.

Mechanisms of chronic stress

Studies revealing the relationship between the immune system and the central nervous system indicate that stress can alter the function of white blood cells involved in immune function, known as lymphocytes and macrophages. People undergoing stressful life events, such as marital turmoil or bereavement, have a weaker lymph proliferative response. After antigens initiate an immune response, these white blood cells send signals, composed of cytokines and other hormonal proteins, to the brain and neuroendocrine system. Cytokines are molecules involved with cell signaling. Cortisol, a hormone released during stressful situations, affects the immune system greatly by preventing the production of cytokines. During chronic stress, cortisol is over produced, causing fewer receptors to be produced on immune cells so that inflammation cannot be ended. A study involving cancer patient's parents confirmed this finding. Blood samples were taken from the participants. Researchers treated the samples of the parents of cancer patients with a cortisol-like substance and stimulated cytokine production. Cancer patient parents' blood was significantly less effective at stopping cytokine from being produced.

Chronic stress and wound healing

The immune system also plays a role in stress and the early stages of wound healing. It is responsible for preparing tissue for repair and promoting recruitment of certain cells to the wound area. Consistent with the fact that stress alters the production of cytokines, Graham et al. found that chronic stress associated with care giving for a person with Alzheimer's Disease leads to delayed wound healing. Results indicated that biopsy wounds healed 25% more slowly in the chronically stressed group, or those caring for a person with Alzheimer's disease.

Chronic stress and development

Chronic stress has also been shown to impair developmental growth in children by lowering the pituitary gland's production of growth hormone, as in children associated with a home environment involving serious marital discord,alcoholism, or child abuse.

Chronic stress and memory

Chronic stress is seen to affect parts of the brain where memories are processed through and stored. When people feel stressed, stress hormones get over-secreted, which affects the brain. This secretion is made up of glucocorticoids, including cortisol, which are steroid hormones that the adrenal gland releases.

Stress and visceral fat

Studies of female monkeys at Wake Forest University (2009) discovered that individuals suffering from higher stress have higher levels of visceral fat in their bodies. This suggests a possible cause-and-effect link between the two, wherein stress promotes the accumulation of visceral fat, which in turn causes hormonal and metabolic changes that contribute to heart disease and other health problems.^[26]

Emotional stress

Emotional stress call the emotional processes accompanying a stress, and leaders to adverse changes in an organism. During a stress, emotional reaction develops before others, making active vegetative nervous system and its endocrine providing. At a long or repeatedly repeating stress emotional excitement can stand, and organism functioning -- to go wrong.

Emotional process, emotional phenomenon, emotional condition, emotion -- the psychophysiological process motivating and regulating activity (behavior, perception, thinking), reflecting subjective value of objects and situations, and presented in consciousness in the form of experience. From emotional processes distinguish affects, emotions, feelings and a mood, excitement can stand, and organism functioning -- to go wrong.

Emotion -- it something that is endured as feeling [feeling] which motivates, will organize and directs perception, thinking and actions. Here the accent is displaced on not less important, motivating aspect of emotional processes, and also the attention that emotional process is presented in consciousness by experience is in addition paid. It is possible to notice also that in activity approach perception, thinking and actions -- are activity components.

Thus, as emotional processes in psychology understand the processes having both mental, and physiological components, being allocated of other psychophysiological processes by that reflect itself for the subject value something, and image corresponding to this value regulating his behavior, thinking and even perception. In consciousness emotional processes are presented in the form of various experiences. For example, fear. Except an obvious mental component, it has also pronounced physiological (increase of allocation of adrenaline, a sweating, delay of digestive processes). The fear reflects itself real or imaginary danger something for the subject, and also prepares an organism for the activity directed on avoiding of danger (feelings become aggravated, blood inflow to muscles increases) get bad.

New researching

Research conducted by Iaroslav Savtchouk, a graduate student Biology and Anatomy at LSU Health Sciences Center New Orleans, has shown that a single exposure to acute stress affected information processing in the cerebellum -- the area of the brain responsible for motor control and movement coordination and also involved in learning and memory formation.

The researchers found that a five-minute exposure to the odor of a predator produced the insertion of receptors containing GluR2 at the connections (synapses) between nerve cells in the brain. GluR2 is a subunit of a receptor in the central nervous system that regulates the transfer of electrical impulses between nerve cells, or neurons. The presence of GluR2 changed electrical currents in the cerebellum in a way that increased activity and altered the output of the cerebellar circuit in the brains of mice.

Our ability to learn from experience and to adapt to our environment depends upon synaptic plasticity -- the ability of a neuron or synapse to change its internal parameters in response to its history. A change in the GluR2 receptor subunit has been observed both during normal learning and memory as well as during many pathological processes, including drug addiction, stress, epilepsy, and ischemic stroke. However, the effect of this change on neuronal function is not fully understood.

"Our results lead to the testable prediction that emotional stress could affect motor coordination and other cerebellum-dependent cognitive functions," notes Dr. Liu. "These results are also applicable to communication in other brain regions and circuits. A long term goal is to alleviate the burden of neurological disorders such as motor dysfunctions, drug addiction, PTSD, and stroke." Next steps include further research to improve our understanding of the role GluR2 insertion plays in normal learning and functioning of the brain, why some neurons contain GluR2-lacking receptors, but not others, and how that affects their role in brain function.

The research was supported by grants from the National Science Foundation and the National Institutes of Health.

Stressor

A stressor is a chemical or biological agent, environmental condition, external stimulus or an event that causes stress to an organism. The word "stress" is from estrecier, to tighten.

An event that triggers the stress response may include:

environmental stressors (elevated sound levels, over-illumination, overcrowding)

daily stress events (e.g. traffic, lost keys, quality and quantity of physical activity)

· life changes (e.g. divorce, bereavement)

· workplace stressors (e.g. high job demand v. low job control, repeated or sustained exertions, forceful exertions, extreme postures)

· chemical stressors (e.g. tobacco, alcohol, drugs)

· social stressor (e.g., societal and family demands)

Stressors have physical, chemical and mental responses inside of the body. Physical stressor produce mechanical stresses on skin, bones, ligaments, tendons, muscles and nerves that cause tissue deformation and in extreme cases tissue failure. Chemical stresses also produce biomechanical responses associated with metabolism and tissue repair. Physical stressors may produce pain and impair work performance. Chronic pain and impairment requiring medical attention may result from extreme physical stressor or if there is not sufficient recovery time between successive exposures. stress distress psychological

Stressors may also affect mental function and performance. One possible mechanism involves stimulation of the hypothalamus, crf (conticotrophin release factor) pituitary gland releases “acth” (adrenocorticotropic hormone) adrenal cortex secretes various stress hormones (e.g. cortisol) stress hormones (30 varieties) travel in the blood stream to relevant organs e.g. glands, heart, intestines. flight-or-fight response. Between this flow there is an alternate path that can be taken after the stressor is transferred to the hypothalamus, which leads to the sympathetic nervous system. After which, the adrenal medulla secretes epinephrine.^[4] Mental and social stressors may affect behavior and how individuals respond to physical and chemical stressors.

Literature

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