in the synaptic lobe of the neuron,how are the impulse passed on to the next neron?
Once a neuron is polarized and an action potential is generated, it travels down the axon and reaches the synapse. The synapse is the space between the axon terminal of one neuron and another cell, or neuron, and it is where the impulse is passed onto another cell/neuron.
1. When the impulse reaches the axon terminal, calcium ion channels open and trigger the movement of synaptic vescicles, that are filled with neurotransmitters, to the synapse.
2. Depending on the neuron type and where the impulse is carried, synaptic vescicles may contain different neurotransmitters. The one that is used mostly in muscle control is acetylcholine.
3. The synaptic vescicles reach the synapse and perform exocytosis, which releases the neurotransmitters into the synapse.
4. The neurotransmitters are then taken up by receptor proteins of the other cells/neurons.
5. The receptor proteins are usually ion channels that changes shape once a neurotransmitter binds to it, and allows ions to enter or exit the cell/neuron.
6. In another neuron, the ion channel allows an influx of ions that creates another action potential.
Once acetylcholine activates the receptor protein, it is immediately broken down into acetic acid and choline by acetylcholinesterase. The breaking down of acetylcholine prevents the neuron from overloading the muscle and prolonging the signal. The acetic acid is then taken up by the neuron to be used again.
The link is a good audio-visual tool to understanding this vital process.
these impulses are carried to next neuron with the help of certain hormones released by those synaptic terminals.among these hormones,the most important is the one named 'ACETYLCHOLINE'.