the endocrine system

• hormones are chemical messengers sent in the blood
• hormones are chemical molecules released directly into the blood
• hormones are carried in the blood to other parts of the body, but only affect particular cells in particular organs - called target organs
• hormones control things in organs and cells which need constant adjustment
• hormones are produced in (and secreted by) various glands, called endocrine glands - these make up your endocrine system
• hormones tend to have relatively long-lasting effects
• pituitary gland:

  • the pituitary gland produces many hormones that regulate body conditions
  • it is sometimes called the master gland because these hormones act on other glands, directing them to release hormones that bring about change
• pituitary gland is found in the brain
• ovaries:

  • produce oestrogen, which is involved in the menstrual cycle
• testes:

  • produce testosterone, which controls puberty and sperm production
• thyroid:

  • this produces thyroxine, which is involved in regulating things like rate of metabolism, heart rate and temperature
• adrenal gland:

  • this produces adrenaline, which is used to prepare the body for the 'fight or flight' response
• pancreas:

  • this produces insulin which is used to regulate the blood glucose level
• thyroid gland is found at the front of the neck
• adrenal gland is found in the heart and in muscles
• pituitary gland secretes the hormones:

  • TSH (thyroid stimulating hormone)
  • FSH (follicle stimulating hormone)
  • LH (luetinising hormone)
• thyroid gland secretes the hormone:

  • thyroxine
• adrenal gland secretes the hormone:

  • adrenaline
• pancreas secretes the hormones:

  • insulin
  • glucagon

  target organ is the liver
• ovaries secrete the hormones:

  • progesterone
  • oestrogen
• testes secrete the hormone:

  • testosterone