ENS Autonomic Somatic preganglionic Sympathetic Parasympathetic neuron ACh ACh ganglionic transmitter 9 Nn receptor Nn receptor Nn receptor postganglionic adrenal medulla neurons > adrenaline released NA ACh ACh neuroeffector into the blood transmitter 0 0 adrenoceptor adrenoceptor M receptor Nm receptor Effector organs Striated muscle 人民只生公版松Sympathetic Parasympathetic ACh ACh ACh Nn receptor adrenal medulla postganglionic neurons adrenaline released NA ACh into the blood M receptor Autonomic Somatic ACh Nm receptor Effector organs Striated muscle Nn receptor Nn receptor adrenoceptor adrenoceptor ENS preganglionic neuron neuroeffector transmitter ganglionic transmitter