Extracellular connective tissue fibrils in the chick embryo

摘要: An electron microscopic study of extracellular connective tissue fibrils in the chick embryo is reported herein. Primary (40–45 A) are first to appear, being present primordia ectodermal boundary (basement) membranes freshly laid eggs. Free microfibrils (40–150 appear by delamination from 24 hours incubation onward. The notochord becomes intensely active forming toward end second day. By 72 free mesenchymal cells producing microfibrils. Axial periodicity acquired relatively slowly their transition unit collagen fibrils. At one week's fibrillar diameters and periodic banding still do not match recognized adult pattern. The hypothesis that a single developmental line leads all fibrous elements supported ontogeny fine structure chick. Microfibrils arise close association with primary fibrils, then notochordal later, more directly mesodermal (mesenchyme, fibroblasts). collagen, reticular elastic fibers light microscopy aggregations alterations material whose descent traceable microfibril.