Hormones

• What are hormones? 


  • chemicals released directly into the blood.
• How are Hormones transported


  they are carried in the blood plasma to other parts of the body but only affect particular cells (called target cells) in particular places
• What do Hormones control?


  things in organs and cells that need constant adjustment
• Where are hormones produced?


  they are produeced in glands
• Adrenaline - source, role and effects


  • source - adrenal glands (on top of the kidneys)
  • role - readies the body for a 'fight of flight' response
  • effects - increases heart rate, blood flow to muscles and blood sugar level.
• Insulin - source, role and effects


  • source - Pancreas
  • role - helps control the blood sugar level
  • effects - stimulate the liver to turn glucose into glycogen for storgae
• Testosterone - source, role and effects


  • source - testes
  • role - main male sex hormone
  • effects - promotes make secondary sexual characteristics, e.g. facial hair
• Progesterone - source, role and effects


  • source - ovaries
  • role - supports pregancy
  • effects - maintains the lining of the uterus
• Oestrogen - source, role and effects


  • source - ovaries
  • role - main female sex hormone
  • effects - controls the menstural cycle and promotes femal sexual characteristics, e.g. growth of breasts
• ADH - source, role and effects


  anti-diuretic hormone

  • source - pituitary gland (in the brain)
  • role - controld water content
  • effects - increases the permeability of the kidney tubes to water
• FSH - source, role and effects


  • source - pituitary gland
  • role - female sex hormone
  • effects - causes an egg to mature in an ovary. stimulates the ovaries to produces oestrogen
• LH - source, role and effects


  • source - pituitary gland
  • role - female sex hormone
  • effects - stimulates the release of an egg from an ovary
• Hormones vs Nerves


  • Hormones have slower messages to Nerves (very high speed)
  • Hormones act for a long time whereas Nerves only act for a very short time
  • Hormones act in a more general way whereas Nerves act on a precise area