Synaptic Transmission

Synaptic transmission is the process whereby one neuron (nerve cell) communicates with other neurons or effectors, such as a muscle cell, at a synapse. A typical neuron has a cell body (soma), branching processes specialized to receive incoming signals (dendrites), and a single process (axon) that carries electrical signals away from the neuron toward other neurons or effectors. Electrical signals carried by axons are action potentials. Axons often have thousands of terminal branches, each ending as a bulbous enlargement, the synaptic knob or synaptic terminal. At the synaptic knob, the action potential is converted into a chemical message which, in turn, interacts with the recipient neuron or effector. This process is synaptic transmission.








Steps in Synaptic Transmission



Information has to travel from one neuron to next, it must be transferred across synaptic cleft, neuro transmitters are chemical messengers that bridge the gap formed by synapes, neurotransmitters are stored in synaptic vesicles at the end of axons. As the action potential reaches the terminal end of the axon, calcium influx through the calcium channels causes these vesicles to fuse with pre-synaptic membrane, the vesicles then dump their contents which are neuro transmitters into the synaptic cleft, the neuro transmitters then diffuse with the post synaptic membrane and bind to specific receptors, however neuro transmitters only act for the brief time, their action is terminated by reuptake pumps that force neurotransmitters back into axon terminal or sometimes by enzymatic degradation in the synaptic cleft ,this removes the neurotransmitters from the synaptic cleft and terminates its effect on post synaptic membrane. Animation showing neurotransmission across the synaptic cleft.