[Morphofunctional characteristics of myotomic muscle fibers in the tail of the Rana temporaria tadpole].

Muscle fibers of the superficial and deep layers of the tail in the tadpole Rana temporaria differ with respect to their ultrastructure, pattern of contractions and electrophysiological properties. The sign of these differences indicates that fibers of the outer layer belong to a slower type, whereas those from the inner one--to a faster type, which corresponds to localization of slow and fast fibers in myotomal musculature of aquatic vertebrates. However, morphological and physiological differences between the outer and inner fibers in the tadpole are expressed to significantly lower extent; on the whole, both of them functionally are less differentiated than it is usually observed in aquatic vertebrates.