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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
6
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pubmed:dateCreated |
1987-8-10
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pubmed:abstractText |
In 11 tibialis anterior muscles of the cat, a single motor unit was characterized physiologically and subsequently depleted of its glycogen through repetitive stimulation of an isolated ventral root filament. Muscle cross sections were stained for glycogen using a periodic acid-Schiff reaction, and single-fiber optical densities were determined to identify those fibers belonging to the stimulated motor unit. Innervation ratios were determined by counting the total number of muscle fibers in a motor unit in sections taken through several levels of the muscle. The average innervation ratios for the fast, fatigueable (FF) and fast, fatigue-resistant (FR) units were similar. However, the slow units (S) contained 61% fewer fibers than the fast units (FF and FR). Muscle fibers belonging to S and FR units were similar in cross-sectional area, whereas fibers belonging to FF units were significantly larger than fibers belonging to either S or FR units. Additionally, muscle fibers innervated by a single motoneuron varied by two- to eightfold in cross-sectional area. Specific tensions, based on total cross-sectional area determined by summing the areas of all muscle fibers of each unit, showed a modest difference between fast and slow units, the means being 23.5 and 17.2 N X cm-2, respectively. Variations in maximum tension among units could be explained principally by innervation ratio, although fiber cross-sectional area and specific tension did contribute to differences between unit types.
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pubmed:grant | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Jun
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pubmed:issn |
0022-3077
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
57
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
1730-45
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pubmed:dateRevised |
2007-11-14
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pubmed:meshHeading |
pubmed-meshheading:3598628-Animals,
pubmed-meshheading:3598628-Cats,
pubmed-meshheading:3598628-Cell Count,
pubmed-meshheading:3598628-Female,
pubmed-meshheading:3598628-Glycogen,
pubmed-meshheading:3598628-Hindlimb,
pubmed-meshheading:3598628-Male,
pubmed-meshheading:3598628-Motor Neurons,
pubmed-meshheading:3598628-Muscle Contraction,
pubmed-meshheading:3598628-Muscles,
pubmed-meshheading:3598628-Regression Analysis
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pubmed:year |
1987
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pubmed:articleTitle |
Maximal force as a function of anatomical features of motor units in the cat tibialis anterior.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.
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