Cellular organization in the synganglion of the mite Macrocheles muscaedomesticae (Acarina: Macrochelidae) - An electron microscopic study


The synganglion is bounded by an extracellular sheath and is divided into the cortex and the neuropile. The cortex contains two glial layers, each of which is composed of a distinctive type of glial cell, and three types of neurons. Type I is the least common and most electron dense, type II is most common, and type III represents neurosecretory cells with a larger volume of cytoplasm than in types I and II. Substantial areas of the neuron cell bodies are unsheathed. A third type of glial cell is found in the neuropile. The first glial layer of the cortex, the perineurium, lies beneath the extracellular sheath and overlies the neuron cell bodies contributing to their ensheathment. In areas lacking neuron cells bodies, the perineurium overlies a second glial layer, the subpermeurium, which is inflected inwards where a group of neuron cell bodies is encountered. The subperineurium contributes to the ensheathment of both the cell bodies of neurons and the nerve fibers. It is confluent with glial cells which arise within the neuropile. The neuropile contains nerve fibers and glial cells and is perforated by the esophageal canal, which is lined by the perineurium and subperineurium. Unsheathed nerve fibers contact each other in three ways: end-knob, longitudinal, and cross contacts. © 1971 Springer-Verlag.

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Zeitschrift für Zellforschung und Mikroskopische Anatomie