Hormones

• Endocrine System


  The way to send information around the body (apart from along nerves) is by using hormones
• Hormones

  Chemical messengers sent in the blood
• How hormones work

  1. Hormones are released directly into the blood

  2. They are carried in the blood to other parts of the body, but only affect particular cells in particular organs (called target organs)

  3. Hormones control things in organs and cells that need constant adjustment
• Endocrine glands


  Glands that produce and secrete hormones
• Hormones tend to have relatively long-lasting effects
• Endocrine glands in the body

  • Pituitary gland
  • Ovaries (females only)
  • Thyroid
  • Adrenal gland
  • Pancreas
  • Testes (males only)
• Pituitary gland


  • Produces many hormones that regulate body conditions
  • Sometimes called the 'master gland' because these hormones act on other glands, directing them to release hormones that bring about change
• Ovaries (females only)


  • Produce oestrogen, which is involved in the menstrual cycle
• Thyroid

  • Produces thyroxin, which is involved in regulating things like the rate of metabolism, heart rate and temperature
• Adrenal gland

  • Produces adrenaline, which is used to prepare the body for a fight or flight response
• Pancreas


  • Produces insulin, which is used to regulate the blood glucose level
• Testes (males only)


  • Produce testosterone, which controls puberty and sperm production in males
• Nerves and hormones both control and coordinate the body's responses