Monday, 30 January 2012

2.85 Reflex


  • Reflex is the simplex type of response. It is very quick and is involuntary (automatically happen without you being able to consciously controlling it). 
  • Reflex reactions are often for self-protection, such as blinking, sneezing, or pulling your hand away from a hot object. 
  • stimulus --> receptor --> sensory neurone --> relay neurone in CNS --> motor neurone --> effector --> response
  • The small nerve called relay nerve in the spinal cord directly connects sensory nerve to the motor nerve so the response can take place. 
  • They know which relay nerve to target because it is encoded within our DNA.
Example :The reflex arc for touching hot object:

Stimulus (pain sensor responding to heat) --> sensory neuron --> spinal cord --> relay neuron --> motor neuron --> effector (muscles) --> response (pulling your hand away from the heat source)

(credits to Michelle)

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