HUMAN SYSTEMS QUESTION 1992:               L.PETERSON/AP BIOLOGY

	Survival depends on the ability of an organism to respond to changes in its 
	environment. Some plants flower in response to changes in day length. Some
	mammals may run or fight when frightened. For both of these examples,
	describe the physiological mechanisms involved in the response.
  

  
  STANDARDS:
     FIGHT OR FLIGHT RESPONSE
  
  ADAPTIVE
  
  __ Turn on needed systems - turn off those not needed; 
     Understanding of Acute vs Chronic response - above and beyond statements in 
     question
  
  MECHANISM
  
  __ Description of nerve pathway - (sensory-associative-motor)
  __ Sympathetic nervous system (autonomic) - activation
  __ Sympathetic system innervates adrenal medulla
  __ Inhibition of parasympathetic by sympathetic
  __ Parasympathetic - counters sympathetic, return to normal homeostasis;
       acetylcholine = neurotransmitter
  __ Epinephrine - adrenalin (cause and effect)
  __ Norepinephrine - noradrenalin (cause and effect)
  __ Source - Adrenalin from adrenal medulla (gland)
  __ Source - Noradrenalin from adrenal medulla and/or sympathetic nerve endings
  __ Receptor molecules on cell membranes
  __ Use of cAMP (second messenger) to elicit intracellular response
  __ Brief vs. sustained - contrasted (initial = sympathetic vs long = adrenal)
  __ Chemical structure of adrenalin/noradrenalin
  
  EFFECT
  
  2 MAX - target tissues and effects
  __ a.  pupillary muscles of eye - dilates pupils
     b.  inhibits salivation
     c.  bronchi of lungs - relaxes
     d.  increases respiratory rate
     e.  heart muscle - accelerates pulse, strengthens contraction
     f.  piloerection - muscles attached to hair follicles
     g.  liver - breaks down glycogen - stimulates release of glucose
     h.  digestive tract - decreases digestive activities - peristalsis
     i.  stomach, small intestine, pancreas - inhibits secretion of digestive enzymes
     j.  stimulates release of fatty acids from fat cells
     k.  peripheral circulation - vessels constrict
     l.  inhibit sex structures
              m.  relax bladder - bowels
     n.  decreased sensation of pain
     o.  "superhuman"
  MAXIMUM - 7 points for this section