Parasympathetic preganglionic neurons originate in which division of the autonomic nervous system?

Parasympathetic preganglionic neurons originate in which division of the autonomic nervous system?

• A. Thoracolumbar Division
• B. Craniosacral Division
• C. Enteric Division
• D. Somatic Nervous System

Answer: (B)

Parasympathetic preganglionic neurons come from the craniosacral division of the autonomic nervous system. Their cell bodies are located in brainstem nuclei (associated with cranial nerves III, VII, IX, and X) and in the sacral spinal cord (S2–S4). From there, these fibers travel to terminal ganglia near or within the target organs, so the preganglionic fibers are relatively long and the postganglionic fibers are short. This contrasts with the sympathetic division, which arises from the thoracic and lumbar regions (thoracolumbar) and has short preganglionic and long postganglionic fibers. The enteric division is a separate intrinsic network within the GI tract, and the somatic nervous system is not autonomic. Therefore, the craniosacral origin best explains where parasympathetic preganglionic neurons originate.

Parasympathetic preganglionic neurons come from the craniosacral division of the autonomic nervous system. Their cell bodies are located in brainstem nuclei (associated with cranial nerves III, VII, IX, and X) and in the sacral spinal cord (S2–S4). From there, these fibers travel to terminal ganglia near or within the target organs, so the preganglionic fibers are relatively long and the postganglionic fibers are short. This contrasts with the sympathetic division, which arises from the thoracic and lumbar regions (thoracolumbar) and has short preganglionic and long postganglionic fibers. The enteric division is a separate intrinsic network within the GI tract, and the somatic nervous system is not autonomic. Therefore, the craniosacral origin best explains where parasympathetic preganglionic neurons originate.