The Construction of Micro-Galvanometer Systems

Downing, A C

doi:10.1088/0950-7671/25/7/302

Cited by 11 publications

(2 citation statements)

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“…The ( uivalent half-thickness b , which is needed for the analysis, was :und by electrical calibration; it was equal to 17 to 18/^ of muscle. The galvanometer (Hill 1948a;Downing 1948) was used with photo-electric nplification, and its magnified deflexion was displayed on the screen of a cathode-,y tube and photographed. Its coil had 4| turns, was 12 mm long and 0-4 mm ide, and was suspended by cadmium-copper wire above and below (see Copeland, owning & Hill 1953, p. 41); it was very carefully balanced to avoid mechanical ibration.…”

Section: Methods Thermopilementioning

confidence: 99%

Chemical change and mechanical response in stimulated muscle

Hill

1953

Proc. R. Soc. Lond. B

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Section: Methods Thermopilementioning

confidence: 99%

Chemical change and mechanical response in stimulated muscle

Hill

1953

Proc. R. Soc. Lond. B

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“…The thermopile was connected to a rapid galvanometer of the type used for all recent myothermic experiments in this laboratory (Downing 1948;Hill 1948 a, 6;; its deflexion operated one beam of a large cathode-ray tube. Photographic records were made in a fixed camera, usually of several linear sweeps (with negligible fly-back time (Attree 1949)) in order to expand the time-scale.…”

Section: Recordingmentioning

confidence: 99%

The absorption of work by a muscle stretched during a single twitch or a short tetanus

Abbott

Aubert

Hill

1951

Proc. R. Soc. Lond. B

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When a stimulated muscle is stretched fairly quickly during the active phase of contraction, it resists strongly and mechanical work must be done in stretching it. What happens to this work? If the length to which the muscle is stretched is not too great no significant part of the work remains as mechanical (elastic) energy after the muscle has relaxed. The total heat produced up to the end of relaxation is greater than it would have been had no work been performed on the muscle, but the excess is too small to account for all the work done. It is concluded that the missing work, about half of the whole, is absorbed, presumably as chemical energy. If a stretch is applied entirely during the relaxation phase, when activity is over but tension is still present, the whole of the work performed reappears as heat. If the view is accepted that the missing work is absorbed in chemical synthesis, it appears that the physical system responsible for mechanical work is reversibly coupled, during the active state, with a chemical system providing the necessary energy; and that this coupling is broken when activity passes off. Other possible hypotheses, however, are discussed. The application to ordinary muscular movement is referred to.

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