Preganglionaarseid

Preganglionic neurons are nerve cells in the autonomic nervous system that originate in the central nervous system and extend to an autonomic ganglion. At the autonomic ganglion, these neurons synapse with postganglionic neurons. The cell bodies of preganglionic neurons are located in the brainstem or the spinal cord. In the sympathetic nervous system, preganglionic neurons originate in the thoracic and lumbar regions of the spinal cord. In the parasympathetic nervous system, they originate in the cranial nerves and the sacral region of the spinal cord. The neurotransmitter released by preganglionic neurons at the ganglion is typically acetylcholine. This neurotransmitter binds to nicotinic acetylcholine receptors on the postganglionic neuron, causing depolarization and initiating an action potential in the postganglionic neuron. The length of preganglionic axons varies; in the sympathetic system, they are generally shorter than postganglionic axons, while in the parasympathetic system, the opposite is true. This difference in length reflects the anatomical organization and function of the two branches of the autonomic nervous system.