Negative feedback

• Thyroxine


  Hormone released by the thyroid gland
• Adrenaline


  Hormone released by the adrenal glands during times of fear or stress
• Adrenaline


  • Increases heart rate
  • Delivers more oxygen and glucose to the brain and muscles
• Fight-or-flight


  The body's response to fear or stress, preparing it to either fight or run away
• Thyroxine


  • Stimulates the body's basal metabolic rate
  • Plays an important role in growth and development
• Negative feedback control of thyroxine levels

  1. Thyroxine level falls

  2. Pituitary gland releases TSH

  3. TSH triggers thyroid gland to release more thyroxine

  4. Increased thyroxine level detected by brain

  5. Brain prevents pituitary gland from releasing TSH

  6. Thyroid gland releases less thyroxine
• Negative feedback cycles are common in the human body, for example in the control of blood glucose and the menstrual cycle