Scanning electron microscopy of human prenatal muscle development.
A scanning electron microscopic study of the development of the human quadriceps was performed in 30 fetuses ranging from 6 to 40 weeks gestation. The results clearly illustrate the hyperplastic phase of myogenesis, showing the differentiation, multiplication and fusion of the myoblasts and the subsequent formation of different generations of myotubes. The myoblasts decrease relatively in number within the developing quadriceps until the 19th week of gestation, and remain afterwards as quiescent satellite cells. The maturation of the myotubes to myofibers and the metabolic differentiation of the fibers are not accompanied by significant changes in their external form in terms of scanning electron microscopy. The hypertrophic phase of myogenesis and general fetal growth can be followed with scanning electron microscopy by the increase in size of the fibers or bundles of fibers, as well as by the differentiation of the connective tissue components of the muscle.
D005314:Embryonic and Fetal Development; D005333:Fetus; D005865:Gestational Age; D006801:Humans; D008648:Mesoderm / Q000166:cytology / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D009132:Muscles / Q000166:cytology / Q000196:embryology* / Q000648:ultrastructure; D013848:Thigh