negative feedback

• What hormone is produced by the thyroid gland?

  Thyroxine
• What does thyroxine control in the body?

  It controls metabolism.
• How does thyroxine affect the reaction of oxygen and food products?

  It controls the speed at which they react to release energy.
• What role does thyroxine play in the body?

  It plays an important role in growth and development.
• How are thyroxine levels controlled?

  By a negative feedback cycle.
• What is a negative feedback control system?

  It responds to changes from the ideal and returns conditions to the set point.
• Where are thyroxine levels detected?

  By the brain.
• What happens when thyroxine levels are low?

  The brain releases TSH hormone.
• What does TSH stimulate the thyroid to do?

  To release thyroxine.
• What occurs when thyroxine levels are higher?

  The brain reduces the amount of TSH released.
• What hormone is produced by the adrenal glands during fear or stress?

  Adrenaline.
• What effect does adrenaline have on heart rate?

  It increases the heart rate.
• How does adrenaline affect the delivery of oxygen and glucose?

  It boosts their delivery to the brain and muscles.
• What is the purpose of adrenaline in the body?

  To prepare the body for 'flight or fight'.
• How is adrenaline different from thyroxine in terms of feedback control?

  Adrenaline is not controlled by negative feedback.
• What are some effects of adrenaline when released into the bloodstream?

  It increases breathing rate, heart rate, and conversion of glycogen to glucose.
• How does adrenaline affect blood flow in the body?

  It diverts blood away from areas like the digestive system towards the muscles.