The endocrine system

• What are hormones?

  • Chemical messengers sent in the blood.
• What do hormones do?

  • Control things in organs and cells that need constant adjustment
  • Produced in various glands, called endocrine glands
  • Tend to have relatively long-lasting effects.
• Examples of glands

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


  Produces hormones that regulate body conditions and is sometimes called the 'master gland'
• Ovaries (females only)


  Produce oestrogen which is involved in the menstrual cycle
• Testes (males only)


  Produce testosterone, which controls puberty and sperm production in males
• Thyroid

  Produces hormones involved in regulating 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
• Nerves


  Very fast action, act for a very short time, act on a very precise area
• Hormones

  • Slower action , act for a long time, act in a more general way