Über die postnatale Entwicklung der Skelettmuskelzellen beim Schwein

Summary On the postnatal development of the skeletal muscle cells in the pig Skeletal muscle cells of pigs up to ten years old were examined histologically and histometrically for age‐related changes. Also examined was the relationship between the changes of the average muscle cell diameter and the age‐related weight changes of the muscles. It was found that, during the entire postnatal period, skeletal muscle cells, despite their high differentiation, continued to develop and developed anew. The two muscle celltypes, red and white, could be differentiated by the end of the first month. The white cells formed the periphery of the muscle cell bundle. They developed from the red muscle cells and can be regarded as more highly differentiated than the latter. The red muscle cells, which retained many postnatal reatures, after the first month formed a group of cells in the center of a muscle cell bundle. Growth of muscle therefore does not only occur by enlargement of the muscle cells (hypertrophy) buy also by their increase in numbre (hyperplasia). The average diameter of the muscle cells in thus related in addition to age, breed, sex, diet and husbandry, also to mitotic intensity and the formation of new muscle cells.