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Fine structure of nuchal organs in some errant polychaetous annelids
Author(s) -
Whittle A. C.,
Zahid Z. R.
Publication year - 1974
Publication title -
journal of morphology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 74
eISSN - 1097-4687
pISSN - 0362-2525
DOI - 10.1002/jmor.1051440204
Subject(s) - biology , cilium , efferent , anatomy , sensory system , annelid , vomeronasal organ , epidermis (zoology) , efferent neuron , vertebrate , ultrastructure , afferent , neuroscience , microbiology and biotechnology , biochemistry , gene
The nuchal organs of polychaetes from four different families (Nereidae, Nephtyidae, Phyllodocidae and Glyceridae) were examined with the light and electron microscopes. In each case, the organ consists of ciliated cells and primary sensory elements. The ciliated cells are similar to the cells of the adjacent epidermis but bear motile cilia. Primary sensory neurons are situated within the organs in Nephtyidae and Phyllodocidae, but are located within the brain in Nereidae and Glyceridae. Each sensory cell gives rise to a distal process which penetrates between the ciliated cells to form an apical sensory bulb bearing modified cilia. Apically these processes are lined with juxtamembranous plaques. The ciliated cells are innervated by efferent axons from the brain, and in Nereis the axons appear to be peptidergic. The elements comprising the nuchal organs closely resemble those of the vertebrate olfactory mucosa.