The Endocrine System and the Fight or Flight Response

• Function of the endocrine system;

  • the endocrine system is a network of glands throughout the body that uses blood vessels to deliver hormones to target sites in the body
  • hormones are secreted into the bloodstream and affect any cell or target site in the body that has a receptor for that hormone
• Glands;

  • the major glands in the endocrine system are the adrenal gland, the reproductive organs (testes and ovaries) and the pituitary gland
  • these glands produce and release hormones
  • these all have an impact on our behaviour
• Examples of glands;

  • the adrenal gland releases adrenaline which stimulates the 'fight or flight' response
  • the pineal gland secretes melatonin and is released during low levels of light to make us drowsy and prepared for sleep
  • the ovaries produce oestrogen and stimulates the release of female sex cells and regulation of the menstrual cycle
• Hormones;

  • these are chemicals that circulate the bloodstream and are carried to the target site in the body
  • it is thought that hormones influence behaviour
  • each hormone has a different effect
  • for example, the hormone testosterone is linked to aggressive behaviour
• Process of the fight or flight response;

  • this happens in response to a threat
  • when we detect a threat the sympathomedullary pathway is activated
  • this activates the autonomic branch of the nervous system
  • this triggers the activation of the sympathetic nervous system
  • the adrenal gland is activated (specifically the adrenal medulla)
  • this produced adrenaline which is released into the bloodstream (cortisol is also released)
• Process of the fight or flight response;

  • this leads to an increase in heart rate, breathing and blood flows to the muscles and away from the stomach
  • digestion slows down because of this
  • pupils dilate and we begin to sweat
  • this cannot be maintained for a long period of time so once the threat is avoided it is the job of the parasympathetic nervous system to restore physiological calm and restore the body to normal