Nematode Sense Organs
1976; Elsevier BV; Linguagem: Inglês
10.1016/s0065-308x(08)60515-1
ISSN2163-6079
Autores Tópico(s)Insect and Arachnid Ecology and Behavior
ResumoNematodes have been found to respond to a wide range of physical and chemical stimuli and must, therefore, possess a variety of sensory receptors coupled with a high degree of nervous co-ordination. This chapter presents the detailed accounts of the various types of nematode sense organs recognized to date, and this has, in some instances, necessitated the introduction of unpublished preliminary information. The chapter correlates the ultrastructural observations with cytochemical and behavioral studies, to assess the possible functional significance of individual receptors. A basic structural arrangement is emerging in many of the sense organs, which have been studied. This arrangement comprises three cell types, (1) a nerve cell, which terminates in the form of one or more highly modified cilia; (2) a non-nerve cell, with a morphology indicative of a secretory function, which has an intimate relationship with the nerve cell; and (3) a second nonnerve cell, which surrounds the other two cell types and often contains bundles of fibers. Relationships between sensory receptors and secretory cells have been described in other phyla, but their functional significance is not fully understood. In the Nematoda, a possible feedback mechanism has recently been suggested, whereby the sensory cilia of the amphid monitor and control the secretory activity of the gland cell in response to external stimuli. Such a system could be classified as it receptor–effector pair of cells, and studies on the bacillary band receptors of Capillaria hepatica and on the intestinal-cloacal valve receptors of Heterakis gallinarum suggest that this primitive arrangement may be a common phenomenon in the phyllim Nematoda.
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