Chemical change and mechanical response in stimulated muscle

Hill, A. V.

doi:10.1098/rspb.1953.0045

Cited by 12 publications

(3 citation statements)

References 7 publications

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“…The dip just after the peak of the corrected record is probably due to heat redistribution into the inactive part of the muscle. The gradient of the corrected heat pro-K. FLOYD AND I. C. H. SMITH duction is constant, and no evidence was seen of an early burst of heat such as that found in twitch fibres (Hill, 1953). Using separate contractions of different durations confirms that the heat rate, measured in the most accurate way as the total heat divided by the stimulus duration, is independent of the contraction's duration up to 60 sec (Fig.…”

Section: Methodssupporting

confidence: 58%

The mechanical and thermal properties of frog slow muscle fibres

Floyd¹,

Smith²

1971

The Journal of Physiology

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SUMMARY1. A study has been made of the mechanical behaviour and the heat production of frog slow muscle fibres in iliofibularis nerve-muscle preparations at 200 C.2. The slow fibre isometric tension and its rate of development increase with stimulation frequency, the increases beyond 30 Hz being relatively small. Relaxation rate also increases with stimulation frequency. The tension-length curve and maximum isometric tension (250 mN. mm-2) are similar to those of twitch fibres. The maximum shortening velocity is estimated to be 0 11 tonus bundle lengths per second.3. For contractions up to 60 sec at 30-50 Hz the slow fibre heat rate is steady at 6 mJ. g'1. sec-1. Slow fibres produce aerobic recovery heat with a time course similar to that of twitch fibres. 4. The accuracy of the results is discussed, and a comparison is made with the properties of twitch fibres. It is concluded that the tensionproducing reactions are thirty times slower in the slow fibres.

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Section: Methodssupporting

confidence: 58%

The mechanical and thermal properties of frog slow muscle fibres

Floyd¹,

Smith²

1971

The Journal of Physiology

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“…4A the maximum rate of heat production is at about 60 msec. The true maximum rate was probably earlier, as the much finer analysis made by Hill (1953b) showed a maximum heat rate before 30 msec. This is before the tension has started to rise and is therefore not altered by the thermoelastic effect.…”

Section: Discussionmentioning

confidence: 99%

Heat production and energy liberation in the early part of a muscular contraction

Woledge¹

1963

The Journal of Physiology

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When a muscle contracts it converts chemical energy into heat and mechanical work. The total amount of this energy 'liberation' can be found, for a cycle of contraction and relaxation, by adding any net external work done to the heat produced. Both these quantities can be directly determined. To find the time course of the energy liberation during a contraction is much harder because not only is the recorded heat production, particularly during relaxation, greatly affected by any inequalities in the muscle (Hill & Howarth, 1957;Hill, 1961), but also two other factors enter into the calculation: (1) the 'internal' work, that is work done by the contractile part of the muscle in stretching the series elastic component and any compliance in the apparatus to which it is connected; to find out how much energy is being liberated by a muscle when the tension is rising (or falling) it is necessary to add (or subtract) the internal work which is being done (or absorbed); (2) the thermoelastic heat; it was shown by Hill (1953 a) that, when the tension falls in a contracting muscle, heat is produced proportional to the fall of tension. Woledge (1961) showed this to be a reversible process, heat being absorbed when the tension rises. Although the molecular nature of the thermoelastic effect is not known it is believed to be the result of some physical process occurring in a muscle when the tension changes; that is, it is not a direct result of the chemical reactions supplying the energy for the contraction. Therefore to find the heat or energy which is being produced by these reactions when the tension is changing it is necessary to correct the observed heat production for the thermoelastic effect: adding to it the heat absorbed by the thermoelastic effect when the tension is rising, and subtracting the heat produced by a fall of tension. The heat production so corrected will be referred to, for convenience, as the 'true' heat production.Neither the internal work nor the thermoelastic heat change can be directly recorded. Both are zero over a complete cycle of contraction and relaxation. The rate of change of each is zero when the tension is constant, therefore the rate of energy liberation can be found without these complications when the tension is constant; for example, (a) during the 'plateau'

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“…Hill [1] has proposed a theory of excitation. He pointed out one every significant factor in excitation.…”

Section: Theory Of Excitation Of Neuronsmentioning

confidence: 99%

Role Of Neural Analysis In Epileptic Attacks With Special Reference To Trace Elemental And Immunological Findings

Mittal¹,

Kumar²,

Ms³

2014

JBEMi

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Neural circuits that are involved in feeding behavior show precise coordination with brain centre that modulate energy homeostasis and cognitive function. The effects of food on cognition and emotions can start before act of feeding itself. The recollection of foods through olfactory and visual sensory inputs alerts the emotional status of the brain. The ingestion of foods triggers the release of hormones or peptides. These hormones or peptides can reach centre such as the hypothalamus and the hippocampus and activate signal -transduction pathways. Epileptic attacks or seizures may be regarded as an emergent property of a network where the underlying physiology oscillatory coordination has given way to excessive coordination. It may be significant that the medial temporal cortex, an area where high amplitude oscillation appears to play a role in episodic memory. It is susceptible to seizure. The trace elements such as Cu, Zn, Fe, Ca, Mg, Na and K are found in the traces in our blood .The excess and deficiency cause different body disorders and affect the immunity of human beings. If the immunity is disturbed in our system many diseases affect our CNS. In the present study we have tried to show how the trace elements and other abnormalities are related to neural system.

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Chemical change and mechanical response in stimulated muscle

Cited by 12 publications

References 7 publications

The mechanical and thermal properties of frog slow muscle fibres

The mechanical and thermal properties of frog slow muscle fibres

Heat production and energy liberation in the early part of a muscular contraction

Role Of Neural Analysis In Epileptic Attacks With Special Reference To Trace Elemental And Immunological Findings

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