Adrenaline & thyroxine

• What directs the secretion of TRH when Thyroxine levels are low?

  Hypothalamus
• What does TRH stimulate in the pituitary gland?

  Secretion of TSH
• What hormone does the pituitary gland secrete in response to TRH?

  TSH
• What is the role of TSH in the endocrine system?

  Stimulates the thyroid gland
• What does the thyroid gland produce when stimulated by TSH?

  Thyroxine
• What happens when there is too much Thyroxine in the body?

  Heart muscle cells contract more quickly
• How does Thyroxine affect metabolism?

  Increases protein and carbohydrate breakdown
• What triggers the hypothalamus to stop TRH production?

  High levels of Thyroxine
• What is the negative feedback loop involving Thyroxine?

  Low levels trigger TRH, TSH, and Thyroxine secretion
• Where does adrenaline travel from and to in the body?

  From adrenal glands to heart muscle cells
• What effect does adrenaline have on heart muscle cells?

  Causes them to contract faster
• How does adrenaline affect blood pressure?

  Increases blood pressure
• What does adrenaline increase the supply of to cells?

  Glucose and oxygen
• How does adrenaline affect respiration in muscles?

  Increases respiration and energy in muscles
• What happens to blood vessels when adrenaline is released?

  Widen for muscles, narrow for non-vital organs
• What is the effect of adrenaline on blood supply to muscles?

  Increases blood supply to muscles
• How does adrenaline affect glycogen in the liver?

  Converts glycogen into glucose
• What is the result of glycogen breakdown in the liver?

  Floods blood with glucose
• What are the effects of Thyroxine on the body?

  • Increases heart muscle contraction speed
  • Increases metabolism
  • Increases protein and carbohydrate breakdown
• What are the effects of adrenaline on the body?

  • Increases heart muscle contraction speed
  • Increases blood pressure
  • Increases glucose and oxygen supply
  • Increases respiration in muscles
  • Widening of blood vessels to muscles
  • Narrowing of blood vessels to non-vital organs
• What is the negative feedback mechanism for Thyroxine regulation?

  1. Low Thyroxine → TRH secretion
  2. TRH → TSH secretion
  3. TSH → Thyroxine secretion
  4. High Thyroxine → stops TRH and TSH production