Nonuniform contraction in the isolated cat papillary muscle
| Autor: | D. K. Stewart, L. L. Huntsman, S. R. Day |
|---|---|
| Rok vydání: | 1977 |
| Předmět: |
Video recording
Contraction (grammar) Physiology Chemistry Microcirculation High stiffness Coronary microcirculation Anatomy In Vitro Techniques Papillary Muscles Myocardial Contraction Microspheres Microsphere medicine.anatomical_structure Coronary Circulation Physiology (medical) Cats medicine Animals Muscle isometric contraction Cardiology and Cardiovascular Medicine Papillary muscle |
| Zdroj: | American Journal of Physiology-Heart and Circulatory Physiology. 233:H613-H616 |
| ISSN: | 1522-1539 0363-6135 |
| DOI: | 10.1152/ajpheart.1977.233.5.h613 |
| Popis: | Microspheres infused into the coronary microcirculation were used as markers to define segments within isolated cat papillary muscles. Video recording and analysis provided measurements of the variations of segment lengths as the muscles contracted at lengths of 76–100% Lmax. In all muscles, segments in the center region were found to shorten during muscle isometric contraction while those in the end regions lengthened. Central shortening was typically 10–15%. In the passive state, segment lengths varied directly with muscle length over a broad range characterized by low force. Segments in the center region, however, displayed an abrupt transition to high stiffness at a certain length while end regions continued to stretch. Force-length relationships obtained for the presumably healthy center segment are significantly different from those obtained for the whole muscle. These results suggest that there may be major difficulties with the interpretation of mechanical measurements on papillary muscles unless contractile inhomogeneity is eliminated or taken into account. |
| Databáze: | OpenAIRE |
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