Expansion
Dorsal root ganglion cells are large and regular; autonomic ganglion cells are smaller and scattered
Expansion
| Feature | Sensory (dorsal root) | Autonomic |
|---|---|---|
| Cell type | Pseudounipolar | Multipolar |
| Size | Large, uniform | Smaller, variable |
| Arrangement | Clustered, often peripheral, with axons running through the centre | Scattered throughout |
| Synapses | None | Present |
| Satellite cells | Complete capsule | Incomplete |
| Nucleus | Central, prominent nucleolus | Often eccentric |
The absence of synapses in a dorsal root ganglion follows from its function: it contains only the cell bodies of primary afferent neurones whose processes pass through without relaying.
Satellite cells are the ganglionic equivalent of Schwann cells, forming a capsule around each cell body and providing metabolic support.
Clinical relevance:
- Herpes zoster lies latent in the dorsal root ganglion and reactivates to give dermatomal shingles
- Sensory neuronopathy from paraneoplastic anti-Hu antibodies or from pyridoxine excess targets the dorsal root ganglion, giving a sensory ataxia with preserved power
- Hirschsprung disease is defined by the absence of ganglion cells in the myenteric and submucosal plexuses, which is why rectal suction biopsy is diagnostic