Structure and contractile properties of the ostial muscle (musculus orbicularis ostii) in the heart of the American lobster

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dc.contributor.authorCavey, Michael J.en
dc.contributor.authorYazawa, T.en
dc.contributor.authorWilkens, J. L.en
dc.contributor.authorter Keurs, H. E. D. J.en
dc.contributor.departmentBiological Sciencesen
dc.contributor.facultyFaculty of Scienceen
dc.contributor.institutionUniversity of Calgaryen
dc.date.accessioned2006-08-14T17:17:04Z
dc.date.available2006-08-14T17:17:04Z
dc.date.issued1999-08-10
dc.description.abstract"Venous" blood enters the crustacean heart through bivalved ostia. Each ostium is a discrete ana- tomical unit that remains functional even when isolated from the heart. Muscle ®bers produce overshooting ac- tion potentials that have a plateau of variable duration in response to nervous drive from the cardiac ganglion or during trains of electrical stimuli. Contractions show summation and facilitation when stimulated by trains of stimuli delivered at rates greater than 0.5 s)1 and 0.2 s)1, respectively. Contraction amplitude increases with stimulating impulse frequency and train duration. Maximum force occurs at 1.2 times the slack length. The morphology of ostial ®bers resembles that of myocardial ®bers. Interconnected bundles of myo®laments occur in both the ostial ®bers and the myocardial ®bers. In ostial and myocardial ®bers, the myo®lament bundles are in- vested by perforated sheets of sarcoplasmic reticulum, and these sheets interface with a network of sarcolemmal tubules to form dyadic interior couplings at the level of the sarcomeric H-bands. The contractile apparatus originates and terminates at intermediate junctions on the transverse cellular boundaries, and the lateral sur- faces of the muscle ®bers are linked by a modest number of communicating (gap) junctions.en
dc.description.refereedyesen
dc.format.extent543113 bytes
dc.format.mimetypeapplication/pdf
dc.identifier.citationT. Yazawa, J. L. Wilkens, H. E. D. J. ter Keurs, M. J. Cavey "Structure and contractile properties of the ostial muscle (musculus orbicularis ostii) in the heart of the American lobster" J Comp Physiol B (1999) 169: 529-537en
dc.identifier.doihttp://dx.doi.org/10.11575/PRISM/35110
dc.identifier.issn0174-1578
dc.identifier.urihttp://hdl.handle.net/1880/43412
dc.language.isoenen
dc.publisherSpringer-Verlagen
dc.publisher.urlhttp://www.springerlink.com
dc.subjectBiologyen
dc.subject.otherContractionen
dc.subject.otherHearten
dc.subject.otherOstiumen
dc.subject.otherHomarus americanus (Crustacea)en
dc.titleStructure and contractile properties of the ostial muscle (musculus orbicularis ostii) in the heart of the American lobsteren
dc.typejournal article
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