The space between the axolemma and the sarcolemma is the primary synaptic cleft. Sarcolemmal foldings form many secondary synaptic clefts. The axon terminal stores secretory vesicles containing acetylcholine. Autonomic postganglionic-effector junctions Autonomic postganglionic fibers frequently form a series of swellings along their course. These varicosities contain mitochondria and numerous synaptic vesicles and may release neurotransmitter within the connective tissues.
Diffusion is required for the neurotransmitter to reach the target cells.
Alternatively, the fibers may lie within a groove on the surface of smooth muscle and make a 'synapse en passant' . A synaptic cleft, postsynaptic cleft, and postsynaptic membrane specializations are present. Injury to cell bodies of a peripheral neuron will not allow regeneration of the nerve. There is some regeneration of nerve fibers under certain conditions. After a short period of leakage of axoplasm, the axon retracts and the axolemma appears to seal the severed ends of the axon.