Negative feedback

• Example: adrenal gland (above kidneys)

  • in times of fear/stress gland produces adrenaline
  • released in blood
  • INCREASES HEART RATE (more oxygen/glucose (aerobic respiration) are delivered in blood to brain + muscles)

  - prepare to fight\run away
• Example: thyroid gland ( base of neck)

  • releases THYROXINE
  • controls METABOLIC RATE - when released it gives a faster rate (speed of reactions of cells)
  • controls growth/development
• Negative feedback-

  • if hormone levels fall, events are triggered which cause the levels to increase again
  • once levels are at usual level events are triggered again for that hormone to stop being released again so it stays level