The Ultrastructuhe of the Spiral Ganglion in the Guinea Pig

Abstract

The spiral ganglion in the guinea pig is composed of uniform bipolar nerve cell bodies, surrounded by sheaths of compact myelin completed with layers of loose myelin.

The perikarya are densely packed with organelles, especially endoplasmic-reticulum, well developed Golgi-zones, mitochondria and osmiophile bodies.

A little group of hitherto not described nerve cells differ significantly from the main part of cells in having no myelin sheath but only one single layer of Schwann cell cytoplasma, little endoplasmic reticulum but many neurofilaments. They have a big nucleolus and their axons are very thin without a sheath of compact myelin. Preliminary experiments of strong white noise stimulation do not show significant alteration in the amount of RNA granules in the perikaryon. There seem to be an increasing number of so-called nuclear caps consisting of several layers of endoplasmic reticulum arranged concentric with the nuclear membrane.