Light- and electron-microscopic investigations into the gastro-intestinal nervous system of the vineyard snail (Helix pomatia).
In the wall of the intestinal tract, two neural plexuses run though. Both of them consist of nerve cells and nerve fibres. The cells belong to the intestinal wall. One part of the fibres is from the nervus intestinalis, the other part belongs to the process system of the parietal ganglion cells. Most of the nerve cells have a unipolar or a bipolar form, but the multipolar forms don't fall within rarities, either. In the cytoplasm, under an electron microscope, there are several endoplasmatic reticula of wide lumina and free ribosomes or those, coordinated in series. And there are but a few mitochondria. The neurosecretory granules, joined by dense-core forms and homogeneous oval granules, are characteristic. The chromatin sits closely on the nuclear membrane in the form of serrated lobes. The greatest part of the nerve fibres are full of neurosecretory granules, there are in the others elliptical granules of large format, the third is dominated by densecore forms. There are added to the nerve fibres of granule content the agranular fibres, containing no granules, as well as glia cells and glial fibrils. In the latter ones, there are plenty of glycogenous granules. Their characteristic constituents are the homogeneous and elliptical gliogranules of large size.
D000818:Animals; D004064:Digestive System / Q000294:innervation; D006372:Helix, Snails / Q000033:anatomy & histology*; D008854:Microscopy, Electron; D009412:Nerve Fibers / Q000648:ultrastructure