Bundle of Unmyelinated Postganglionic Neuronal Filaments whose Neuronal Bodies Lie in a Boundary Cord Ganglion. The gray connecting branches, one for each spinal nerve (2x31 pcs); connects the spinal nerve with the corresponding border cord ganglion.
The grey junction branch contains the nerve fibres which, within the range of the connected spinal nerve, are intended to supply the smooth muscle of the blood vessels (vasomotor function), the sweat glands of the skin (sudomotor function) and the smooth muscle cells of the skin (pilomotor function) which cause the "hair to rise" and which then produce "goosebumps".