Contractile filaments in cells of regenerating tendon.

An extensive cytoplasmic fibrillar system has been observed in fibroblast-like cell of regenerating tendon. It consists of bundles of actin filaments, which often show a cross-striated appearance due to electron dense bodies occurring throughout their length. The functional role of this contractile apparatus seems to be related to the process of movement and orientation of the newly formed cells and to the retraction of the regenerating tendon.