title: [Ultrastructural findings on collagen fibers of tendon sheaths from the rat tail].
abstract: Rat tail tendon sheaths have been studied by electron microscopy and freeze-etching techniques. Pictures from thin sections have shown the presence of three different sheaths: a) a sheath commun to all tendons, (paratenon) formed by collagen fibrils differently orientated with a variable diameter (20nm 200nm) b) a specific sheath for every tendon, (peritenoneum) which is composed by different layers: the external ones present collagen fibrils of wide and variable diameter (20nm-200nm). The internal ones present collagen fibrils of uniform and small diameter (50nm-60nm). Between these fibres layers, there is evidence for the presence of fibrocits forming continuous cellular layers. c) a sheath surrounding tendon fascicles, (endotenoneum) formed by small and uniform collagen fibrils and a continuous cellular layers. Replicas of freeze-fractured collagen fibrils having a variable diameter show a straight arrangement of their microfibrils.
mesh_terms: D000818:Animals; D003094:Collagen / Q000032:analysis*; D005614:Freeze Fracturing; D008854:Microscopy, Electron; D051381:Rats; D011919:Rats, Inbred Strains; D013623:Tail; D013710:Tendons / Q000648:ultrastructure*
chemical_list: D003094:Collagen
vernacular_title: Indagine ultrastrutturale delle fibrille collagene delle guaine del tendine della coda di ratto.