White muscle fibres

Usually known as mosaic muscle in these fish, as the white muscle fibres are interspersed with individual red muscle cells (Walker and Emerson, 1978 Johnston, 1982). This mixed type of muscle is not considered in detail here. 

Brill, R.W. and Dizon, A.E. (1979). Red and white muscle fibre activity in swimming skipjack tuna, Katsuwonus pelamis. Journal of Fish Biology 15,679-685. 

A microcalorimeter scan can also be used to provide a determination of the nature of meats [34]. As shown in Figure 21, samples of chicken breast and thigh show different profiles which may be due to differences in their pH and contraction state as well as different content of red and white muscle fibres. It is also important to consider whether the material is examined in isolation versus in situ because the thermal properties may be different. 

The different muscle fibre types of fish may be cited as examples of tissues with widely differing fractional protein synthesis rates cardiac muscle has often been found to have fractional protein synthesis rates which are approximately four fold higher than those of white muscle fibres (Haschemeyer et al. 1979 Smith et al. 1980 Fauconneau 1985 Houlihan et al. 1986 Houlihan et al. 1988b McMillan and Houlihan 1988). 

Kumar, D., White, C., Fairweather, I. and McGeown, J.G. (2004) Electrophysiological and pharmacological characterization of K+-currents in muscle fibres isolated from the ventral sucker of Fasciola hepatica. Parasitology 129, 779-793. 

Nag, A.C. and Nursall, J.R. (1972). Histogenesis of white and red muscle fibres of the trunk muscle of a fish, Salmo gairdneri. Cytobios 6,227-246. 

Individual muscles are made up of different types of fibre, the proportions of which determine the contractile properties of the muscle. Muscles fibres have been classified in a number of different ways. The original division into red and white muscle is an oversimplification, since there is much variation... 

Generally speaking, fish red muscle has higher fractional rates of protein synthesis than white muscle, results which parallel those found from mammals (e.g. Gold-spink et al. 1984). The slow tonic, predominantly oxidative fibres in the leg of the crab Carcinus also have higher fractional rates of protein synthesis than the fast phasic, predominantly glycolytic muscle fibres (El Haj and Houlihan 1987). These wide differences between tissues rates of protein synthesis raise the question of the different proteins synthesised in different tissues. A comparison of the fractional rates of protein synthesis in subcellular fractions from fish red muscle and white muscle has revealed the following features ... 

HAVS follows from exposure to vibrations in the range 2-1500 Hz which causes narrowing in the blood vessels of the hand, damage to the nerves and muscle fibres and to bones and joint evidenced by pain and stiffness in the joints of the upper arm. The impaired circulation of blood to the fingers leads to a condition known as vibration white finger (VWF). The most damaging frequency range is 5-350 Hz. 

FIGURE 2.4 Cl). Transverse section of M. pectoralls major of pigeon. The figure shows the Interflheral (IN. F.) localization of AA around the muscle fibres WF White fibres ... 

Less intense physical activity is often referred to as aerobic exercise, because it involves mainly red muscle fibres (and type IIA white fibres) and there is less accumulation of lactate. 

Martin, W., S. Murphree and J. Saffitz, 1989. Beta-adrenergic receptor distribution among muscle fibre types and resistance arterioles of white, red, and intermediate skeletal muscle. Circul. Res. 64, 1096-1105. 

It is now clear, from the results of several workers, that the biochemical characteristics of a muscle fibre are also profoundly influenced by the nature of the associated nerve. Several years ago Gutmann s group [22] reported that the concentration of glycogen and potassium is higher in fast muscles and that reinnervation of the soleus muscle (slow) with nerve fibres which normally supplied a fast muscle led to an increase in these constituents in the soleus. A marked tendency towards interconversion of the enzyme pattern in red and white fibres following cross-innervation of the soleus and flexor hallucis longus (fast) muscles was demonstrated histochemically by Romanul and Van der Meulen [23] and by Dubowitz and Newman [24], and other workers have described similar effects of cross-innervation on other biochemical activities which differ in red and white muscle. 

Roughly speaking, slow muscles are red muscles whilst fast muscles are white, Jthough exceptions are known (see, for example, [14]). Muscle redness or whiteness is determined by the predominating fibre type most muscles contain a mixture of fibre types. Histochemical studies have shown the existence of two main types of fibre, the red (Type I) and white (Type II) fibres. (A third intermediate type is also recognized [15] and others have been reported.) The Type I fibres, which are usually smaller, have more numerous mitochondria and thus a high... 

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