Monday, 6 February 2012

2.89 - Hormones

2.89 understand the sources, roles and effects of the following hormones: ADH, adrenaline, insulin, testosterone, progesterone and oestrogen.


Adrenaline: is produced by adrenal glands (above the kidney) and is released in times of excitement, fear or stress. Adrenaline helps prepare the body for action in the following ways:

  • Glycogen is converted to glucose in the liver, so more glucose reaches the muscles as a source of energy for the rapid contractions needed for sudden action
  • Increases heart rate so that more glucose and oxygen are delivered to the muscles for energy release
  • The bronchioles widen so that more air reaches the lungs
  • Blood vessels to the brain widen so that more glucose and oxygen is delivered to these organs
  • Blood vessels to the gut and other organs narrows allowing blood to be diverted to more life-saving organs
  • Hairs are raised

ADH: is made in a gland in your brain and controls the level of water in your body.


Insulin: The pancreas makes insulin. The insulin tells the liver to take glucose out of your blood so it is changed into glycogen in the liver . Insulin lowers blood glucose(sugar)  levels back to normal


Testosterone & Oestrogen are hormones that bring about the changes to our bodies that occur at puberty
Testosterone is the male hormone and brings out these changes in boys:

  • the testes start making sperms
  • hair starts to grow on the face and body
  • The voice deepens
  • the muscles develop
Oestrogen is the female hormone and brings out these changes in girls:
  • The ovaries start to release eggs
  • hair starts to grow on parts of the body
  • the breasts develop
  • the hips widen
  • periods start

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