Endocrine system and Fight or Flight

• Endocrine system is a collection of glands around the body that regulate bodily functions, growth and psychological factors. These act by releasing chemical messengers called hormones into the bloodstream.
• Pituitary gland controls the release of hormones from other glands. This is also referred to as the master gland.

  • Hormones released - ACTH (Adrenocorticotropic hormone).
• Hypothalamus links the nervous system to the endocrine system in combination with the pituitary gland. It is also responsible for maintaining homeostasis.

  • Hormones - CRH (Corticotropin-releasing hormone).
• Pineal glad regulates sleep patterns, keeping the body to a day and night circadian rhythm.

  • Hormone - Melatonin.
• Thyroid gland regulates metabolism, which is the rate of energy use in the body.

  • Hormone - Thyroxine.
• Thymus gland stimulates the development of T cells that work in the immune system in helping with disease resistance. This is active until pubity.

  • Hormone - Thymosin.
• Pancreas regulates blood sugar levels. A problem with this organ leads to diabetes.

  • Hormone - Insulin and glucagon.
• Adrenal glands regulate biological effects of fight or flight. This includes the increase in heart rate, blood supply to muscles, sweating etc.

  • Hormone - Adrenaline and Cortisol.
• Ovaries and testes are both reproductive organs which help in the development of characteristics in both males and females, appearing at puberty.

  • Hormone - Oestrogen (ovaries), Testosterone (testes).
• The fight or flight response is an evolutionary survival mechanism in response to threat.
• Chronic stress is a long term form of stress due to prolonged emotional pressure. This often occurs in situations where the individual feels unable to control the situation.
• Effects of Adrenaline and Noradrenaline:

  • Increased blood flow to the brain and skeletal muscles.
  • Decreased blood flow to systems that are not time to critical (eg skin, digestive and immune systems).
  • Dilated pupils for improved vision.
  • Increase in breathing rate to allow for more oxygen intake.
  • Increased sweat production to remove heat.
  • Psychological effects of increased anxiety, attention and alertness.
• Stress related illness:

  • Constant triggering of the fight or flight response has long term effects on physical and mental health.
  • Fight or flight response shuts down the immune and digestive system, causing high blood pressure and anxiety.
  • This also leads to an increased risk of heart disease, obesity, IBS (irritable bowel syndrome) and a general lower resistance to disease which may result in depression.