Coordinated responses

• what is the flight or fight response?

  • an instinctive response to a potentially dangerous situation, where the body triggers a series of physiological processes e.g. increase heart and breathing rate
• what occurs during coordination of flight or fight response?

  • coordination of sympathetic NS and adrenal-cortical system, endocrine and nervous
  • sympathetic - activates adrenal medulla releases adrenaline and noradrenaline (stress hormones causing physiological changes) into bloodstream, impulses activate glands and smooth muscle
  • A-C system - releases corticotropin, pituitary gland secretes ACTH which arrives at adrenal cortex and releases approx 30 hormones into bloodstream helps prepare for threat
• what are some specific physiological changes in flight or fight?

  • increased heart rate - pumps more oxygenated blood around body
  • pupils dilate - take in as much light for better vision
  • smooth muscles of airways relax - allow more oxygen into lungs
• what are some functions of adrenaline?

  • trigger cells to undergo glycogenolysis so that glucose is released into bloodstream - allowing respiration rates to increase so more energy is available for muscle contraction
• what are some properties of adrenaline?

  • binds to receptors on surface of liver cell membrane and triggers a chain of reactions inside the cell
• what does adrenaline cause after binding to cell membrane?

  • causes conformational change in membrane
  • causes G protein to move and bind to adenylyl cyclase (now a holoenzyme), disassociation of G protein causes conformational change
  • holoenzyme can now carry out reactions, cascade reactions in glycogenolysis