Myothermic apparatus

doi:10.1098/rspb.1928.0029

Cited by 24 publications

(5 citation statements)

References 10 publications

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“…The near agreement between the average (0-917) of the 40 values obtained with Hill's (1928a) method and that (0 840) of the other three investigations, does not leave any possibility of a large error of calibration in the former. The most likely conclusion is that the 1928 equipment gave heats, on the average, about 10 % too great, which agrees well enough with the 14% excess of Feng's values of (dH/dt)/Pl over ours (p. 321 above).…”

Section: Discussionsupporting

confidence: 52%

“…The 19 open circles represent the results recorded in four earlier papers (Hartree & Hill, 1921, 1922, 1928aHartree, 1932). The observations were all made between 15 and 200 C, and the results were reduced to 170 C in the way described above.…”

Section: Resultsmentioning

confidence: 99%

“…Methods and equipment of Hill (1928a) The methods and equipment described by Hill (1928a) were used in a large number of investigations in many of which absolute values were required. It was very desirable, therefore, to try to find out whether errors of calibration affected these results also.…”

Section: Discussionmentioning

confidence: 99%

“…

The existence of so large a discrepancy led first to a critical examination of the methods now used.

…”

mentioning

confidence: 99%

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An examination of absolute values in myothermic measurements

Hill¹,

Woledge²

1962

The Journal of Physiology

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The impulse to the investigation described in the following pages arose from the recent discovery of a serious discrepancy between the absolute values, obtained by current methods, of the heat produced in isometric contractions of frog sartorii and those reported in several papers published between 1921 and 1932 (Hartree & Hill, 1921, 1922, 1928aHartree 1932 Myothermic experiments are of two general types: (a) those in which absolute values are not required, the heat being compared with itself under different conditions, for example, at various temperatures, with different durations and frequencies of stimulus, before and during partial fatigue and in the several phases of contraction, maintenance, relaxation and recovery; and (b) those requiring accurate calibration, in which the heat is being compared in absolute units with mechanical work (positive or negative), with mechanical tension, with chemical and osmotic changes and with 02 consumption. In (a) an error of calibration is usually unimportant; in (b) it can be serious.The existence of so large a discrepancy led first to a critical examination of the methods now used. Apart from the finding that in some minor respects their accuracy could be somewhat improved, they survived the test. The frogs were the same (English Rana temporaria) and the conditions (temperature, etc.) were similar: only different instruments and methods were used. The absolute values, therefore, of the heat reported in the older papers referred to were, without doubt, considerably and consistently too great. This could only be due to an error of calibration. In five other papers, however, published during the same period (Fenn, 1923(Fenn, , 1924Wyman, 1926; Hartree & Hill, 1928b, c), for which similar methods and instruments were used, there was no direct evidence of an error of calibration, either for or against. In these papers, work (W) and heat (H) were compared under various conditions of shortening or stretch. It seemed unlikely that an error of calibration which gave heat values 50 % or more

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Section: Discussionsupporting

confidence: 52%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

“…

The existence of so large a discrepancy led first to a critical examination of the methods now used.

…”

mentioning

confidence: 99%

See 2 more Smart Citations

An examination of absolute values in myothermic measurements

Hill¹,

Woledge²

1962

The Journal of Physiology

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“…The method of heat measurement was that of A. V. Hill (8). Only a few modifications, which were required to adapt it to the new type of muscle, need be mentioned.…”

mentioning

confidence: 99%

The heat production of smooth muscle

Bozler¹

1930

The Journal of Physiology

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OUR knowledge of the physiology of muscular contraction is based mainly upon studies of vertebrate skeletal muscle. The study of a very different type of muscle might be expected to be of value (a) for the understanding of its special properties, and (b) to show which of the properties of skeletal muscle are common also to other types and may, therefore, be regarded as properties of muscular tissue in general. In the course of comparative studies on unstriated muscle(2) an easily obtainable and very favourable preparation was found in the retractor of the pharynx of the large edible snail (Helix pomatia): this muscle was used for all the experiments on heat production reported here.Preparation. The muscle is a part of the columellar muscle. It is attached at one end to the axis of the shell and at the other to the ventral side of thepharynx. The shell is first removed, care being taken not to break the middle part of its axis, which is later used as an attachment for the muscle. After removing the front part of the mantle, which is very slimy, the body wall is cut dorsally from near the top up to the head. The genital organs are removed. If the stomach be then lifted with forceps, the pharynx and the retractor muscle attached to it beneath the cesophagus become visible. The pharynx is then cut off the body near the mouth. This should be done as quickly as possible since it involves cutting the connection of the muscle with the central nervous system, which forms a ring round the pharynx. Strong stimulation of the ganglia produces a vigorous contraction of the retractor muscle which persists for a long time, even after complete removal from the body. The axis of the shell with the muscle attached to it is cut off. Only as much of the axis is left as is necessary for the attachment. The other parts of the columellar muscle attached at the same place are removed as far as possible.

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Bioenergetics of Exercising Humans

Brooks

2012

Comprehensive Physiology

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Human muscles, limbs and supporting ventilatory, cardiovascular, and metabolic systems are well adapted for walking, and there is reasonable transfer of efficiency of movement to bicycling. Our efficiency and economy of movement of bipedal walking (≈30%) are far superior to those of apes. This overall body efficiency during walking and bicycling represents the multiplicative interaction of a phosphorylative coupling efficiency of ≈60%, and a mechanical coupling efficiency of ≈50%. These coupling efficiencies compare well with those of other species adapted for locomotion. We are capable runners, but our speed and power are inferior to carnivorous and omnivorous terrestrial mammalian quadrupeds because of biomechanical and physiological constraints. But, because of our metabolic plasticity (i.e., the ability to switch among carbohydrate (CHO)- and lipid-derived energy sources) our endurance capacity is very good by comparison to most mammals, but inferior to highly adapted species such as wolves and migratory birds. Our ancestral ability for hunting and gathering depends on strategy and capabilities in the areas of thermoregulation, and metabolic plasticity. Clearly, our competitive advantage of survival in the biosphere depends in intelligence and behavior. Today, those abilities that served early hunter-gatherers make for interesting athletic competitions due to wide variations in human phenotypes. In contemporary society, the stresses of regular physical exercise serve to minimize morbidities and mortality associated with physical inactivity, overnutrition, and aging.

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Myothermic apparatus

Cited by 24 publications

References 10 publications

An examination of absolute values in myothermic measurements

An examination of absolute values in myothermic measurements

The heat production of smooth muscle

Bioenergetics of Exercising Humans

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