Selye’s Based on Walter Cannon’s Homeostasis

Selye’s based on Walter Cannon’s Homeostasis: maintaining a constant internal environment was vital to complex organisms (also made “fight or flight” Allostasis: maintain stability through change to meet perceived and anticipated demands ● Body protects itself from internal and external stress by activating the sympathetic nervous system (SNS), the hypothalamic pituitary gland (HPA) axis, and changes in metabolism, heart rate, BP, and immune system. -> releases stress hormones (adrenaline, cortisol, glucocorticoids) ● Prolonged hormones and stress: Allostatic load/overload: wear and tear on brain and body, decreased function and pathological changes for brain to interact with body ● Resilience: capacity to avoid negative biological, psychological, and social outcomes of stress Coronary Heart Disease (CHD): buildup of waxy substance, plaque, in heart arteries ● Stress releases cytokines from immune system, part of inflammation, increases risk of CHD, affects liver functioning as its not active during SNS so it can’t clear the fat and cholesterol from the bloodstream -> clogged arteries, heart attacks, strokes ● Brunner study: middle-aged men questioned about stress, diet, lifestyle for heart disease factors: obesity, high blood sugar, high triglycerides (bad cholesterol), and low levels of HDL (good cholesterol). Stress and stress hormone production were strongly linked to all these biological risk factors. More stress = more likely to exhibit these risk factors ● Chandola study: 9/11 heart health = 53% increase in heart ailments 3 years following. Work stress associated with risk of CHD due to effects of stress on automatic nervous system (ANS, controls automatic processes, breathing, digestion) and glandular activity/function. Also due to metabolic dysfunction Type 2 Diabetes: middle adulthood, body becomes resistant to insulin or no longer secret enough insulin to maintain normal glucose levels. Weight gain, pancreas insulin levels become less efficient as body size increases. Insulin resistance – higher levels of immune system’s cytokines (stress) chronic stress promtoes systemic inflammation which interferes with insulin signaling -> worsens metabolic dysfunction. Insulin resistance increases glucose and fat buildup > increases inflammation (positive feedback loop) Type 1 Diabetes: autoimmune disorder, failure of pancreas to secrete enough insulin ● Increased risk of alzhemier’s disease ● Novak study: Sweden men monitored for health and stress factors with no history of diabetes or CHD. 45% higher chance of developing diabetes with prolonged stress ● Toker study: high work stress with low social support = higher diabetes risk ● Stress from behavioral and biological factors can influence healthy individuals Cancer: cells divide without stopping, create tumors to affect normal organ functioning, invade, fail, and kill the organism ● Stress - suppressing effect on immune system for unchecked cancer growth ● Natural Killer (NK) cell: immune system cell that suppresses viruses and tumors ● Hormone Adrenaline (stress); interferes with protein that suppresses cancer cells ● Adrenaline and noradrenaline can cause mistakes (telomeres) to control cell production. Mistakes pile up and cause tumors ● Hassan study: mice with human cancer cells had treatment. If stressed, the cancer treatments failed ● No association between job stress and cancer risk Children with family stress have higher rates of fever/illness ● Stress improves function of natural killer cells (opposite from adults) ● Work stress in middle age increases physical/mental disabilities in old age