Sympathetic (thoracolumbar) outflow
Outflow · T1–L2 N_N at ganglion NA on α/β
Preganglionic cell bodies sit in the intermediolateral cell column of T1–L2 (occasionally L3). Short cholinergic preganglionic fibres synapse near the cord; long noradrenergic postganglionic fibres reach every organ, and the adrenal medulla adds a hormonal arm.
Detail
- Segments
- T1–L2 (some texts T1–L3) intermediolateral cell column
- Ganglion transmitter
- Acetylcholine on nicotinic (N_N) receptors
- Postganglionic transmitter
- Noradrenaline on α1, α2, β1, β2, β3 — except sweat glands (acetylcholine on M3)
- Divergence
- One preganglionic fibre drives up to ~20 postganglionic neurones, allowing mass discharge
When it goes wrong
Spinal cord injury above T6, after spinal shock resolves, with a full bladder or faecal impaction
Autonomic dysreflexia: unopposed sympathetic discharge below the lesion causes severe hypertension with pounding headache and flushing above the lesion, and reflex bradycardia via the intact vagus
Practise this structure
1 question in the bank tagged Autonomic.