Response to stress

• the two main divisions of the autonomic nervous system include the sympathetic and parasympathetic nervous systems
• sympathetic and parasympathetic nervous systems actions are mostly antagonistic - they work in opposition to each other
• the parasympathetic nervous system maintains and conserves body energy and functions
• the sympathetic nervous system prepares the body to expand energy for fight or flight
• gut

  • sympathetic nervous system - stops digestion
  • parasympathetic nervous system - increases digestion
• salivary glands

  • sympathetic nervous system - inhibits (prevent) saliva production
  • parasympathetic nervous system - increases saliva production
• heart

  • sympathetic nervous system - increases heart rate
  • parasympathetic nervous system - decreases heart rate
• liver

  • sympathetic nervous system - stimulates glucose production
  • parasympathetic nervous system - stimulates bile production
• bladder

  • sympathetic nervous system - increases urination
  • parasympathetic nervous system - decreases urination
• eyes

  • sympathetic nervous system - dilates pupils
  • parasympathetic nervous system - constricts pupils

  A) dilated

  B) constricted

  
• lungs

  • sympathetic nervous system - dilates bronchi
  • parasympathetic nervous system - constricts bronchi
• fight or flight response

  anxiety and fear are important for survival as they act as mechanism to protect the body against stress and danger
• the sympathetic nervous system controls the 'fight or flight' phenomenon due to it having control over necessary bodily changes needed when we are faced with situation were we may need to defend or escape
• sympathetic nervous system - prepared state
• parasympathetic nervous system - relaxed state
• chronic stressor is long term and creates a pituitary adrenal response
• acute stressors are short term and creates a adrenal medullary response
• the amygdala is an area of the brain that is mobilised when an individual faces a threat
• the amygdala associates sensory signals with emotions associated with fight or flight

  • sends distress signal to hypothalamus
  • hypothalamus communicates with rest of body through SNS
  • two different responses body can initiate - depends on if threat is acute or chronic
• acute - immediate - short term
• chronic - ongoing - long term
• the hypothalamus functions like a command centre in the brain
• the hypothalamus communicates with rest of the body through the sympathetic nervous system
• acute and chronic stressors

  A) hypothalamus

  
• evaluation - limitation - tend and befriend

  • men and women respond differently to stressful situations
  • taylor et al suggests women show 'tend and befriend' behaviour - protecting offspring and themselves through nurturing and forming alliances with other women
  • women have differing responses as they are often primary caregiver - fleeing may put offspring at risk
  • studies suggest there may be physiological response to stress that inhibits fight - release of oxytocin increases relaxation
• evaluation - limitation

  tend and befriend - limitation because fight or flight suggests both male and females will either run or fight from situation but women tend to 'tend and befriend' with other females to protect their offspring
• evaluation - limitation - negative consequences

  • stressors of modern day rarely require physical activity that fight or flight can prepare for
  • when stress response being repeatedly activated - impacts humans wellbeing due to increased blood pressure leading to physical damage to blood vessels - heart attack
  • too much cortisol suppresses the immune response shutting down process that fights infection
  • too much stress on the body can have negative consequences
• evaluation - limitation - alternative response

  • gray argues first reaction to threat is not fight or flight but instead it is avoid confrontation
  • he argues most animals typically first show the 'freeze response' when animal is hyper vigilant
  • the advantages of this response includes 'freezing' focuses attention and makes them look for new info in order to make the best response for particular threat
• evaluation - limitation - positive behaviours in response to stress

  • von dawans et al challenged idea that men only respond with fight or flight under stress whilst women are more prone to 'tend and befriend'
  • he count acute stress can lead to greater cooperative and friendly behaviour - explains 9/11 attack (everyone came together)
  • one reason for this may be humans are fundamentally social animals and it is the protective nature of humans that helps us to survive
• evaluation - limitation - genetic basis for gender differences

  • some studies show there being genetic basis for gender differences
  • lee and harley found SRY gene found on male chromosomes which directs male development - promoting aggression resulting in fight or flight response
  • gene may make males respond to stress in this way by releasing stress hormones such as adrenaline
  • the lack of SRY genes combined with action of oestrogen and oxytocin may prevent this response to stress in females