Why does the flow of signals in a synapse from axonal end of one neuron
to dendritic end of another neuron take place but not in the reverse
direction ? Explain.
Answers
Answer:
The reason why this happens is that when signals or impulse travel through the axon and reach the end certain chemicals are released. These chemicals are present in the synaptic knobs which are only located at the axonal end. This chemical help the impulse to travel through the synaptic gap ( gap present between two consecutive neurons that is about 2nm or 0.2nm in chemical and electrical synapses respectively).
Since these chemicals are not present in the dendritic end impulses won't cross in the reverse direction through the synaptic gap.
Hope it helps..
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↪ The nerve impulses are transmitted from one neuron to the the other in the form of electric impulses.
↪ They enter through the dendrites, move through axon and reach the nerve ending.
↪As soon as they reach there, they need to be converted into chemical signals and electric signals are unable to cross the gap i.e. synapse.
↪Thus chemical called 'neuroteansmitters' are released from the vesicles that move from nerve ending of one neveon to the dendrite of next one.
↪ As soon as the chemicals reach the dendrite top, they again get connected to electrical impulses and move on.
↪They chemicals are released and move only in one direction and do not revers in order to reach there destieration that can be spiral {they are released in one direction} cord or brain or effectors in order to deliver the message.