Describe the synaptic junctions between the neurons of the autonomic and somatic

The neuroeffector junction describes the synapse between neurons of the autonomic nervous system and their effector organs. The anatomy of these structures is quite different from the typical neuron-neuron synapse. The postganglionic neuron does not have a discrete, well-defined axon terminal. Rather, those neurons contain numerous swellings along their length (varicosities). Within those varicosities, neurotransmitters ( norepinephrine and acetylcholine) are synthesized and stored in vesicles, as occurs at axon terminals. However, while the swellings contain the voltage-gated calcium channels that are required for the release of neurotransmitter, they also contain the voltage-gated sodium and potassium channels that are required for the propagation of an action potential along the length of the axon. At the same time, the distance between a varicosity and the postsynaptic membrane is greater than what is observed in the synaptic cleft of other synapses.

In the somatic nervous system, the synapse ( neuromuscular junction) couples the motor neuron to skeletal muscle fibers. The terminal bouton of the motor neuron contains acetylcholine stored in vesicles. The motor end plate is a specialized region of the skeletal muscle that contains an invagination where nicotinic receptors are located. Surrounding this invagination are local regions of high acetylcholinesterase concentration.