VIDEO: Transmission of excitation at the synapses

Previous knowledge of the nerve cell in order to understand the transmission of excitation

The nerve cell, in which the impulse transmission takes place at the synapses, consists of a cell body, which you also call soma, and one or more processes.

• Note that the processes are long extensions of the cytoplasm and that you can distinguish them into dendrites and the axon.
• Dendrites are relatively short and often tree-like branching processes. Note that they catch the incoming excitation and direct it to the body of the nerve cell.
• The neurite is a particularly long process that can be over a meter long. If you look at a nerve cell under the microscope, you will see that the axon branches like a tree at its end. Neurites conduct the excitation from the body of the nerve cell to other cells.
• Note that the axon ends on a dendrite or soma in another cell. The juncture between the endings of axons and other cells is called a synapse.


Synapse - function simply explained

For biology class or university, you need to know what the function of a ...

instagram viewer
• Remember that the transmission of excitation at the synapses is a chemical process.

This explains the transmission at the synapses

The synapses are switching points for the transfer of excitation from one nerve cell to a second or from one nerve cell to the successor organ, for example your muscle. In this case, the synapse is called the motor endplate and the nerve cells that carry the impulses are called motor neurons.

• Chemical agents called neurotransmitters are necessary for the transmission of excitation to the synapses.
• Remember that the important carrier substances are acetylcholine, noradrenaline, dopamine, serotonin, glutamate, glycerine and γ-aminobutyric acid that are produced in the nerve cells, stored in vesicles and released by an incoming action potential in the synaptic gap will.
• The neurotransmitters diffuse in the synaptic gap to the postsynaptic membrane, where they are bound to receptors. Please note that depending on the neurotransmitter and receptor, the transmission of excitation to the synapses may or may not be inhibited.
• If the excitation is passed on, there is an influx of sodium into the adjacent cell, which you call an excitatory synapse. If the sodium influx does not take place, the stimulus is not passed on and you call the synapse inhibitory.
• A neurotransmitter takes between half a second and a millisecond to work. Note that the messenger substances are then broken down and transported back to the synapses. For example, the enzyme cholinesterase destroys the acetylcholine and the nerve cell's ability to excite is restored.