Review Article

The Leech Nervous System: A Valuable Model to Study the Microglia Involvement in Regenerative Processes

Figure 1

(a) Diagram of leech nervous system containing a head ganglion, 21 body ganglia, and 7 fused tail ganglia joined by connectives. (b) The dorsal view of the ganglion presents packet glial cells enveloping neuron cell bodies. The axonal processes passing through the neuropil are prolonged into connectives. The neuropil lies dorsomedially and contains two macroglial cells. Thousands of microglial cells are distributed in ganglia and connectives. The nervous system is enclosed in the outer capsule which is covered on the outside by a visceral layer of the endothelium (lining the ventral blood sinus). (Reprinted, with permission, from [8]).