ISSN:
1432-1351
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary The lower anterior thorax of the lobster contains a set of three proprioceptors, bilaterally arranged, that monitor the movements of structures in the area, in particular the mandible and the lower oesophagus. These proprioceptors have been named mouthpart receptors 1, 2 and 3 (MPR 1, 2, 3). They form a functional whole, with MPR 1 situated at the front, and MPR's 2, and 3, at the rear, of a single ligament that spans the region between, the anterior border of the lower thorax (at the base of the antennary insertion), and the posterior end of the oesophagus. MPR 1 is composed of 4 or 5 sense cells whose dendrites insert onto a small elastic receptor strand, that itself is attached to the main strand. MPR 2 and 3 also insert on receptor strands that attach at the rear of the main strand, but at somewhat different positions and angles. Physiologically these cells are mechanically sensitive, responding in a variety of ways to stretch and displacement of the main strand. In MPR 1 at least one and sometimes two units fire continuously for long periods at very constant frequency. This frequency is modulated by movement, the frequency either rising or falling depending upon whether the mandible is raised or lowered. Other units are phasic, and velocity sensitive. In MPR 2, and 3, phasic and phaso-tonic units are both present, but few continually firing receptors. MPR 1 seems more affected by mandibular movements, MPR 2 and 3 by oesophageal movements. The possible role of these receptors in the control of mouthpart movements, and the activity of the foregut, is discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00341114
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