WORKSHOP IN HISTOLOGY, CYTOLOGY AND EMBRYOLOGY - 2016

Chapter 4. TISSUES

Slide 54. Striated skeletal muscle tissue (rabbit tongue).

Staining: hematoxylin and eosin or iron hematoxylin.

Magnification: x400.

Muscle fibers in the Tongue are arranged in three mutually perpendicular planes. The surface of the tongue is covered with stratified squamous epithelium, which forms papillae on its dorsal surface and a flat layer on the ventral surface.

In longitudinal section, muscle fibers (1) have a cylindrical (rectangular) shape. The surface of a muscle fiber is covered by the sarcolemma (2), which appears as a distinct outline under the Microscope. Oval-shaped nuclei (3) are located beneath it. In thin sections of muscle fibers, we can distinguish longitudinal striation formed by myofibrils and transverse striation resulting from the presence of dark (anisotropic) and light (isotropic) discs. Thin layers of loose Connective Tissue, the endomysium (4), are observed between the muscle fibers.

In cross-sections (5), striated muscle fibers are rounded in shape. The nuclei are round and located at the periphery of the fiber beneath the sarcolemma. In the sarcoplasm, we can distinguish dark dots representing cross-sections of myofibrils (6). Clusters of myofibril cross-sections, separated by areas of light sarcoplasm, are called Cohnheim's fields (7).

A well-developed, thick layer of loose connective tissue, the perimysium, is located between groups (bundles) of muscle fibers.

Class="center">Cytology/practical/practical.files/image062.jpg" width="332"/>

Slide 54. Striated Skeletal Muscle tissue (rabbit tongue).