Adrenaline & Thyroxine

• Which organ is adrenaline released from?

  Adrenal gland
• What effect does adrenaline have on heart rate?

  It increases heart rate
• When is adrenaline released?

  When you're scared
• Adrenaline causes changes in the body to prepare for a ‘fight or flight’ response.


  • Increase heart rate
  • Increase blood pressure
  • Increase blood flow to muscles 
  • Increases blood sugar (glucose) levels
• Adrenaline causes the conversion of which substances? 

  Glycogen ➔ glucose
• Which organ is thyroxine released from?

  Thyroid gland
• What is the main role of thyroxine?

  To increase your metabolic rate
• Which organ is TSH released from?

  Pituitary gland
• The hormone TSH is involved in the regulation of thyroxine levels. 

  What does TSH stand for?

  Thyroid stimulating hormone
• Does thyroxine stimulate or inhibit the pituitary gland from releasing TSH?

  Inhibit
• Does TSH stimulate or inhibit the thyroid gland from releasing thyroxine?

  Stimulate 
• Which type of feedback is involved in the regulation of thyroxine levels?

  Negative feedback
• Describe what will happen when thyroxine levels are too high.

  If thyroxine levels are too high the thyroxine will inhibit the pituitary gland from producing TSH.

  TSH stimulates the thyroid gland to produce thyroxine, so less TSH means that the thyroid gland won't release as much thyroxine, and so over time thyroxine levels in the blood fall back to normal.

  This is an example of negative feedback.