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Bladder Nerve Varicosities
Top Left: A cartoon showing preterminal and terminal varicosities (enlargements) on terminal branches of a postganglionic axon. (Varicosities are labeled with asterisks.)
Bottom & Right: Electron micrographs of postganglionic nerve terminal branches in a feline urinary bladder. Axon branches (A; yellow) are ensheathed by lemmocytes/Schwann cells (sc; green) and surrounded by myocytes (my; brown). At varicosities, the axonal enlargements bulge beyond lemmocyte processes and contain numerous synaptic vesicles (arrows). These synaptic vesicles release acetylcholine which diffuses throughout the extracellular space and binds to muscarinic receptors on myocytes.
Bottom & Right: Electron micrographs of postganglionic nerve terminal branches in a feline urinary bladder. Axon branches (A; yellow) are ensheathed by lemmocytes/Schwann cells (sc; green) and surrounded by myocytes (my; brown). At varicosities, the axonal enlargements bulge beyond lemmocyte processes and contain numerous synaptic vesicles (arrows). These synaptic vesicles release acetylcholine which diffuses throughout the extracellular space and binds to muscarinic receptors on myocytes.
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