Biological Explanations

The Biological Explanations of Stress

General Adaptation Syndrome (GAS)

  • General Adaptation Syndrome is Hans Selye’s concept that the body has a standard, three-step defence response to stressors.
  • The three stages are alarm, resistance, and exhaustion.
  • In the alarm phase, the body prepares for ‘fight or flight’ by releasing stress hormones.
  • In the resistance phase, the body attempts to resist the stressor and return to normal. However, if the stress continues, the body may remain on high alert.
  • Finally, in the exhaustion phase, continuous stress depletes the body’s resources, potentially leading to burnout or physical illnesses.

Role of the Autonomic Nervous System

  • The Autonomic Nervous System (ANS) plays a crucial role in the body’s response to stress.
  • The ANS has two branches, the Sympathetic Nervous System (SNS) and the Parasympathetic Nervous System (PNS).
  • When a stressful situation is perceived, the SNS is activated leading to a number of physiological responses such as increased heart rate and adrenaline production.
  • Once the threat is gone, the PNS then works to restore the body to a more relaxed, resting state.

Role of the Endocrine System

  • The Endocrine System also plays a pivotal role in our body’s reaction to stress.
  • Activation of the stress response triggers the Hypothalamic-Pituitary-Adrenal (HPA) axis and results in the production and release of cortisol, a stress hormone.
  • Prolonged stress can lead to overactivation of the HPA axis, resulting in excessive cortisol levels and potential health issues such as immune suppression and memory problems.

Genetic Factors in Stress

  • Individual susceptibility to stress and stress-related diseases may be influenced by genetic factors.
  • Some genes, such as those involved in serotonin and cortisol production, could potentially make certain individuals more susceptible to the effects of stress.
  • It is worth noting however that both genes and environment interact in complex ways to determine our stress responses.

Neurotransmitters and Stress

  • Stress can influence the balance of several neurotransmitters, including serotonin, dopamine, and noradrenaline.
  • For instance, chronic stress can cause depletion in serotonin levels, which is associated with depression.
  • Stress can also increase levels of dopamine, which could lead to increased alertness but excessive levels can cause psychosis.