Stress as a bodily response - PSYA2 (AQA)

  • Stress and Stressors
  • Acute stress - sympathodullary pathway
  • Chronic stress - pituitary adrenal system
  • Immune System and effects of stress on the immune system
  • Fight or Flight (Cannon - 1914)
HideShow resource information
View mindmap
  • Stress as a bodily response
    • Fight or Flight
      • Cannon (1914)
        • Early evolutionary adaption that is useful in dealing with short term physical threats
        • When body is under threat need ability to stand/fight or run away
    • Acute stress - sympathomedullary pathway
      • Occurs when exposed to acute/short term threat/stress
      • Hypothalamus in charge of stress response - sends signals to sympathetic ganglia (via nerve impulses) when triggered from short lived/acute threat
        • Hypothalamus triggers the sympathetic nervous system
      • Sympathetic Ganglia
        • Connected to internal organs - when activated affects functioning of lungs, heart and digestive system
        • Causes lungs/heart to work harder but suppresses non emergency bodily processes such as digestion
        • Connected to Adrenal Medulla
      • Adrenal Medulla
        • Stimulated by sympathetic branch of ANS via nerves
        • Releases adrenaline/nor-adrenaline into bloodstream
        • Hormones stimulate sympathetic ganglia to keep activity at a high level
        • Effects are Sweating and increased heart/breathing rate
          • Because we need more energy/oxygen supplied to muscles, so energy reserves have to be mobilized into sugars and fatty acids in bloodstream
    • Chronic stress - pituitary adrenal system
      • When stress response triggered - signal sent to pituitary gland
        • This happens by releasing CRF (Corticotrophin releasing factor) into bloodstream which then travels to the pituitary gland
      • The pituitary gland
        • Controls glands of endocrine system (glands that secrete hormones)
        • When activated by the hypothalamus it releases ATCH, which activates the adrenal cortex
      • Adrenal Cortex
        • Releases chemicals called corticosteroids into bloodstream
        • Cortisol has a number of functionsin stress response
          • Releases stored glucose to help maintain steady supply of sugar for continued energy - also controls swelling after injuries and lowers sensitivity to pain
    • What is stress and a stressor?
      • Stress
        • Subjective experience of a lack of fit between a person and the environment
        • Perceived demands of s situation are greater than perceived ability to cope
      • Stressor
        • Any event that causes stress reaction in body
        • Includes environmental stressors (workplace) and life changes (illness/death)
        • Individual differences and sense of control modify effects of stressors
    • Stress and the immune system
      • The immune system
        • Bodies defense mechanism for foreign substances, also controls substances in the body
        • Protects body against infection - network of cells and chemicals that seek out and destroy invading antigens
          • stress can reduce immune system functioning by reducing concentration of cytokines (help ward off infection)
            • it consists of cells distributed throughout the body to fight disease, white blood cells (leukocytes) identify and fight illness/disease
        • The presence of antigens leads to the production of antibodies
          • Several kinds of white blood cells within immune system - T cells, B cells and natural killer cells
            • T cells destroy invaders, T-helpers increase the activity in the immune system
              • T-cells mature in the thymus (an endocrine gland) and leukocytes are produced in the bone marrow and then migrate to thymus
                • High levels of corticosteroids can shrink the thymus gland - preventing T-cells from maturing
            • Natural Killer cells are involved in the fight against viruses and tumours
      • Stress can effect the immune system by shutting it down - if alot of stress corticosteroids can suppress the immune system
      • Effects of stress on body and immune system
        • Direct biological effects - hormonal changes (cortisol)
        • Maladaptive coping behavior - smoking, drinking (indirect effects)
        • Emotionally mediated effects on diet and activity levels - exercise and socializing (indirect effects)
      • The endocrine system
        • link between stress and illness due to effect of endorphines - bodys natural painkillers
        • Endorphin's - biochemical substances released at times of pain/anxiety
          • Decrease sensations of pain but suppress immune system activity - especially in natural killer cells


No comments have yet been made

Similar Psychology resources:

See all Psychology resources »See all Stress resources »