11.3.4 Hormones vs Nervous Control

• What are hormones?

  Chemical messengers
• How do hormones travel in the body?

  They travel in the blood
• What do hormones target?

  Target organs or cells
• What destroys hormones in the body?

  The liver
• What system releases hormones into the blood?

  The endocrine system

  
• What is adrenaline?

  A hormone released from adrenal glands
• What effect does adrenaline have on pupils?

  Pupils dilate
• How does adrenaline affect heart rate?

  Heart rate increases
• What happens to breathing rate when adrenaline is released?

  Breathing rate increases
• What does adrenaline do to glycogen?

  Breaks down glycogen, raising blood glucose
• What is the effect of adrenaline on blood flow to the brain?

  Vasodilation of arteries increases blood flow
• How does adrenaline affect blood flow to the gut?

  Vasoconstriction of arteries decreases blood flow
• What are the main differences between hormonal and nervous control?

  • Hormonal control uses chemical messengers (hormones)
  • Nervous control uses electrical signals (nerve impulses)
  • Hormonal responses are slower but longer-lasting
  • Nervous responses are faster but shorter-lived