Morphological and histochemical properties of tongue muscles in cat.

The morphology of the tongue muscles was studied by in situ dissection as well as by histological and histochemical methods. By means of the latter an anatomical reassessment of attachments and fiber courses was made. The histochemistry was studied in sections stained for myofibrillar adenosine triphosphatase (mATPase), succinic dehydrogenase, NADH diaphorase, phosphorylase, esterase, glycogen and lipids. Fibers of type I and type II were identified, and the latter were subdivided into II1 (highly glycolytic), II12 (intermediately glycolytic and lipolytic) and II123 (highly lipolytic). In the extrinsic muscles, the fibers were 19-25% type I (mean diameter 27 micrometers) and 75-81% type II (37 micrometers); the three type II subgroups appeared in equal proportions, each accounting for 22-30% of the total fiber amount. Pars longitudinalis superior m. hyoglossi and pars longitudinalis inferior m. styloglossi contained only type II fibers, mainly type II12 (67% and 46%, respectively), of diameters like those in m. hyoglossus and m. styloglossus. The intrinsic muscles also consisted entirely of type II fibers (23 micrometers). II123 fibers predominated in m. verticalis (83%), which has only 10% H12 and 6% II1, whereas the fiber composition of m. transversus was more balanced: 37% type II1, 32% II12 and 31% II123.