the endocrine system

• Key features of endocrine system

  • It works alongside the nervous system to control vital functions in the body through the action of hormones
  • Works more slowly than the nervous system (seconds instead of milliseconds), as hormones have to travel though the bloodstream
• glands

  • Glands are organs in the body that produce hormones
  • Key endocrine gland = pituitary gland:
  • Located in the brain
  • Called the ‘master gland’
  • It controls the release of hormones from all other endocrine glands in the body
• hormones

  • hormones are secreted in the bloodstream and affect any cell in the body that has a receptor for that particular hormone
• examples of hormones/glands:

  • Thyroid gland = produces thyroxine
  • Affects cells in the heart and cells throughout the body which increase Metabolic rates => affects growth rates
  • Pineal gland = produces melatonin
  • Regulates circadian rhythm and sleep
  • Adrenal gland = produces cortisol and adrenaline
  • cortisol = maintains blood sugar, regulates inflammation, immune response
  • Adrenaline = responsible for fight or flight response
• Endocrine system and ANS work together (eg during stressful event)

  • Stressor is perceived by hypothalamus which activates the pituitary
  • The sympathetic nervous system is now aroused
  • Adrenaline (stress hormone) is released from the adrenal medulla into the bloodstream
  • This delivers the aroused state causing changes in target organs in the body (sympathetic state/fight or flight response)
  • Parasympathetic nervous system (rest and digest) = takes over once the threat has passed - returns the body to it’s resting state (reduces the activities of the body that were increased by the actions of sympathetic branch)
• Glands in the body