All these while, I was wondering why the adrenal medulla only has direct stimulation (PREganglionic neuron) from the brain (CNS) without having POSTganglionic neuron when transmitting impulses unlike other organs.
Look at the figure below
Only PREganglionic neuron transmitting impulses to adrenal medulla (sympathetic)
Why?? so here is the answer
Medullary cells are derived from the embryonic neural crest and, as such, are simply modified neurons.In particular, they are modified postganglionic cells of the sympathetic nervous system that have lost their axons and dendrites, receiving innervation from corresponding preganglionic fibers. Moreover, as the synapses between pre- and postganglionic fibers are called ganglia, the adrenal medulla is actually a ganglion of the sympathetic nervous system.
Sources: Lecture notes and wikipedia
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