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)
- Created by: Abby Donald
- Created on: 26-03-14 16:49
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
- Cannon (1914)
- 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
- When stress response triggered - signal sent to pituitary gland
- 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
- 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
- stress can reduce immune system functioning by reducing concentration of cytokines (help ward off infection)
- 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
- T-cells mature in the thymus (an endocrine gland) and leukocytes are produced in the bone marrow and then migrate to thymus
- Natural Killer cells are involved in the fight against viruses and tumours
- T cells destroy invaders, T-helpers increase the activity in the immune system
- Several kinds of white blood cells within immune system - T cells, B cells and natural killer cells
- 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
- The immune system
- Fight or Flight
Comments
No comments have yet been made