Lecture 1. Occupational Stress Stress Physiology The primary role of the physiological stress response is to: Mobilise the bodies fuel reserves Convert fuel to forms suitable for transportation and use Increase oxygen in the parts of the body that need it for fight or flight Shut down unnecessary energy usage The physiological stress response involves many components including: Figure 1. A simplified representation of the central and peripheral components of the stress system, their functional interrelations and their relationships to other central nervous system pathways involved in the stress response. CRH: corticotropinreleasing hormone, LC/NE sympathetic system: locus ceruleus/norepinephrinesympathetic system, POMC: proopiomelanocortin, AVP: arginine vasopressin, GABA: aminobutyric acid, BZD: benzodiazepine, ACTH: corticotrophin, NPY: neuropeptide Y, SP: substance P. Activation is represented by solid green lines and inhibition by dashed red lines. Hans Selye The &quot;Father&quot; of Stress &quot;The Stress of Life&quot; book 1956 Stress is a &quot;natural&quot; process just as aging is a &quot;natural&quot; process. It will happen to everyone at some time. Stress &quot;responses&quot; occur for both positive and negative situations. &quot;Stressors&quot; trigger &quot;stress&quot; responses Stressor &quot;that which produces stress.&quot; &quot;Syndrome of Being Sick&quot; Nonspecific effects that occur when a person is ill. Disease or injury causes specific effects. Being sick also leads to other effects that are general and not specific to disease. Malaise, fatigue, tiredness, weakness, lack of motivation, poor sleep, not hungry Initial concept about stress &quot;Homeostasis&quot; The body has a &quot;natural&quot; resting point of physiological equilibrium There are normal fluctuations from the natural resting point Activity (physical, mental, emotional) can create fluctuations in homeostasis The body strives for homeostasis Selye's Early Observations Conducted animal studies where harsh Enlargement of Adrenal Gland's cortex Shrinking or atrophy of thymus, spleen, lymphatic structures Bleeding stomach and duodenum ulcers exposures of any sort produced the same pattern of adverse physiology: GAS General Adaptation Syndrome Three stages of response to stressors: Alarm Reaction Resistance and adaptation Exhaustion and collapse Stage of Alarm Increase in heart rate Increase in blood pressure Increase in sweating Adrenaline, noradrenaline, cortisol Energy resources mobilized and used Decrease in blood flow to extremities Depletion of stress hormones Messed up homeostasis Reduced ability to respond physiologically to stressors over time In total, the stress response involves the release and modulation of over 50 hormones including: Encephalins Endorphins Melatonin Stimulating Hormone Thyroxin Thyrotrophin Vasopressin Aldosterone Renin Growth Hormone Glucagon Prolactin Parathyroid Hormone Calcitonin Gastrin Stage of Resistance Homeostasis reestablished but at a different &quot;abnormal&quot; level of physiology The ability to react to stressors returns as stress hormones are available Organism seems stabilized at new level, and to have adapted to stress Stage of Exhaustion After some time of effective adaptation the organism becomes exhausted physiologically At some point the organism's physiological system and organs collapse, become dysfunctional In Selye's animals the extreme result was death In people serious stressrelated diseases can occur, some of which may lead to death CHD/CVD, Hypertension, Ulcers, immune system disorders, psychological disorders Colds, flu, disease susceptibility Musculoskeletal and muscle disorders Mental health disorders Factors in the &quot;Stress&quot; Response The level of stressors The extent of time of exposure to stressors Recurrence of exposures Heredity Personality Physical health status at exposure Age Gender Psychological status at exposure Diet (?) Coping mechanisms available and used More Selye and Beyond Musculoskeletal effects such as muscle tension and sensitivity of muscle fibers Inflammatory response Body's energy production and use system including the liver, hormones of digestion and action, muscles Metabolic disruption (insulin, thyroxin) Digestion, excretion and urination systems Perceiving, thinking and judgment (83, 84). (85, 86, 87). Figure 6. <a href="/keyword/schematic-representation/" >schematic representation</a> of the detrimental effects of chronic stress on adipose tissue, bone and muscle metabolism. GH: growth hormone. Stimulation is represented by solid green lines and inhibition by dashed red lines. (96, 97, 98). . Figure 10. <a href="/keyword/schematic-representation/" >schematic representation</a> of the central neurocircuitry and its altered activity in acute stress and melancholic depression (chronic hyperactivation of the stress system). Hyperfunctioning amygdala, hypofunctioning hippocampus and/or hypofunctioning mesocorticolimbic system (MCLS) could be associated with chronic hyperactivation of the PVN CRHAVP system and predispose to melancholic depression. PVN: paraventricular nucleus, CRH: corticotropin releasing hormone, AVP: arginine vasopressin. Stimulation is represented by solid lines and inhibition by dashed lines. Stimulation is represented by solid green lines and inhibition by dashed red lines. Summary # 1 Brain initiates stress response Direct effects are created by signals to organs and muscles Indirect effects are created by hormones released into bloodstream Effects are systemic Effects are for action Effects are for adaptation to stressors Summary # 2 Body mobilizes resources to react to stressors (energy, attack) Repeated responding leads to depletion of resources Chronic responding leads to GAS type process Mid stage of GAS changes the homeostasis of the body End stage of GAS creates serious damage or death