1. Mechanism of reflex action: There are series of sequential events in which reflex action is completed:
2. Stimulus is picked up by any receptors, e.g. pricking of a needle in the hand, causes skin to be a receptor.
3. Sensory impulse is formed in grey matter of spinal cord. It receives sensory impulse, interprets it and generates motor impulse.
4. The cyton of motor neuron present in the ventral horn of grey matter and axon conducts motor impulse from spinal cord to effector organ. This is further carried by dendrites innervating the skin.
5. Impulse is carried to the association neuron by axon of sensory neuron, when impulse reaches the end of the axon there is a synapse.
6. Transmission takes place by releasing acetylcholine from the synaptic buttons at the end of the axon.
7. It fills the synaptic gap and helps in chemical transmission of the impulse from axon of one neuron to dendron of the other neuron. Once the impulse reaches the dendrites of association neuron; axonic button releases an enzyme, acetylcholine esterase which neutralizes the acetylcholine and again a synaptic gap is formed. This mechanism helps to receive new impulse or avoid the mixing of different impulses.
8. The association neuron receives sensory impulse, interprets it, analyses it and generates motor impulse. Motor impulse again travels through synapse between association neuron and motor neuron.
9. Impulse travels through motor neuron and reaches the effector organ like skeletal muscles or the gland. The effector organ gives a proper response like contraction of the muscles or secretion by the gland.
