Die Embryologie der Haut

Synopsis: The mammalian hair-fibre, together with the “inner root-sheath” ( i.e. the axial layers of the follicle wall), grows upward by a proximal addition of cells. Changes in the inner root-sheath are responsible for the final shape and surface sculpture of the fibre. At its distal limit the inner root-sheath disintegrates owing to the effect of a de-keratinizing chemical agent. A bent, undulated, or “crimped” fibre is due to a differentiated progress of the changes leading to keratinization of the “fibre cortex”. The cells which give rise to a “medulla” are different chemically and less compressible than cortical cells.