[Histometric indicators of the structure of the leg muscles in children, adolescents and young adults].
In preparations of mm. tibialis anterior, soleus and vastus lateralis from 16 persons at the age of 4--21 years, died from some accidents, a relative content of the connective, fatty tissue and of two histochemically distinguished types of myons, visually revealed according to succinatedehydrogenase (SDG) activity have been determined. Besides, a minimal diameter of muscle fibres and SDG activity in them cytophotometrically defined have been measured. The connective tissue content is not essentially changed with age, and that of the fatty tissue--has a certain tendency to increase. The part of the I type myons is significantly increased from the m. vastus lateralis towards the m. tibialis anterior and from the m. tibialis anterior towards the m. soleus but is not corrected with age. A definite direct dependence between age and the middle diameter of myons is revealed, as well as between age and the ratio of the II and I types of the myon diameter which are expressed by means of the linear regression equations. When investigated cytophotometrically, in most of the muscles a bimodal distribution of the myons is noted according to SDG activity. However, in united histograms, made for similar muscles, the muscle fibres demonstrate practically a normal distribution, that speaks in favour of some relativity in isolating the myon types.
D000273:Adipose Tissue / Q000166:cytology; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000886:Anthropometry; D002648:Child; D002675:Child, Preschool; D003239:Connective Tissue Cells; D006801:Humans; D007866:Leg / Q000033:anatomy & histology*; D009132:Muscles / Q000033:anatomy & histology* / Q000166:cytology
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