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Stages in the formation and keratinization of the cortex of the wool fiber

1971; Academic Press; Volume: 36; Issue: 3-4 Linguagem: Inglês

10.1016/s0022-5320(71)80108-9

1878-2345

Ralph E. Chapman, R. T. Gemmell,

Skin and Cellular Biology Research

Differentiation of the cortical segments of the wool fiber commences in the suprabulbar region of the follicle with the formation of small macrofibrils adjacent to desmosomes. In orthocortical cells, the macrofibrils are without distinct microfibril formation below a level about one-quarter the distance up the follicle, at which level a microfibril-matrix complex appears to resolve throughout the macrofibrils formed so far. In paracortical cells, the macrofibrils consist initially of distinct microfibrils between which matrix subsequently forms at a faster rate until matrix production catches up with microfibril formation at a level about one-quarter the distance up the follicle. Synthesis of both microfibrils and matrix continues in each cortical segment until the cells are replete with microfibril-matrix complex at about two-fifths the distance up the follicle. Beyond this is a zone of low sulfhydryl content extending to a level three-fifths the distance up the follicle where ultrastructural changes indicative of final keratinization occur.