Describe the reflex action with the help of labelled diagram.

Explanation

The reflex action is completed in a series of events . For e.g., when the hand is pricked with a needle , immediately hand is withdrawn from the source .
(i) Pricking of needle stimulates skin receptors by receiving stimulus .
(ii) Sensory impulse is formed and it is carried by dendrites innervating the skin .
(iii) Impulse is carried to the association neuron by aron of sesory neuron .
(iv) Impulses reaches the end of axon there is synapse . (v) Synapse is filled by neurotransmitter substance acetylcholine .
(vi) Association neuron receive sensory impulse interprets it , analyses it and generates motor impulse.
(vii) Motor impulse again travels through symapse between association neuron and motor neuron.
(viii) Impulse travels through motor neutron and reaches effector organ like skeletal muscle of glands .
(ix ) Effector organ gives a proper response like contractions of muscle or secretion by gland .