SYMPATHETIC GANGLION

Vegetative ganglia serve to transmit information  from visceromotor systems originating in the CNS nuclei before the postganglionic fibres reach the target structures. From outside the ganglion is enveloped by the capsule from the dense connective tissue; tiny septa enter the parenchyma to supply it with the blood. Structure of vegetative ganglia differs from cerebrospinal ganglia.
Ganglionic cells have features of multipolar neurons (Fig. 1B in white). Perikaryon is large (although not reaching a size of somatosensory ganglia). The neuroplasm contains the Nissl substance that also enters the dendrites. The perikaryon is surrounded by few satellite cells (amphicytes - in red). The more distant is the vegetative ganglion from the truncus sympaticus, the less amphicytes surrounds their perikaryon. Due to many cytoplasmic processes of multipolar ganglionic cells passing through a layer of satellite cells, this layer is not so continuous. Nevertheless in ganglia of the truncus sympaticus a layer of  around ganglionic cells is more developed (Fig. 1B) than in cells of intramural ganglia that are surrounded only by a layer of the endoneurium. The basal lamina of amphicytes (magenta) is continuous with the basal lamina of Schwann cells. The endoneurium contains many unmyelinated (autonomic) nerve fibres (blue). Bodies of ganglionic cells are mixed with vegetative nerve fibres, i.e. their components are not well arranged and are scattered throughout the entire ganglion. The dendrites of ganglionic cells are synapsed with endings (dark green) of other vegetative neurons - their axons are indicated in light green colour. This means the autonomic ganglia contain synapses (on the contrary to cerebrospinal ganglia).

Fig. 1. Arrangement of structures in the sympathetic ganglion. A. Multipolar ganglionic cells (black) are connected via synapses on their surface with preganglionic fibres. Axons of ganglionic cells leave as the postganglionic nerve fibres, which are unmyelinated; Schwann cells are shown in blue. B. 3D reconstruction of ganglionic cells. Illustration legend can be found in the text. Author: R. Krstic; colours: J. Mokrý.