Muscle Tissue

Muscle tissue is categorized on the basis of a functional property, the ability of its cells to contract

Muscle cells are characterized by large amounts of the contractile proteins actin and myosin in their cytoplasm and by their particular cellular arrangement in the tissue. To function efficiently to effect movement, most muscle cells are aggregated into distinct bundles that are easily distinguished from the surrounding tissue. Muscle cells are typically elongated and oriented with their long axes in the same direction (Fig. 3.3). The arrangement of nuclei is also consistent with the parallel orientation of muscle cells.

Although the shape and arrangement of cells in specific muscle types, e.g., smooth muscle, skeletal muscle, and cardiac muscle, are quite different, all muscle types share

stains more intensely with the blue dye. Also, note the relatively fewer nuclei. X540. b. A Mallory-stained specimen of dense connective tissue, showing a region composed of numerous, densely packed collagen fibers. The few nuclei (N) that are present belong to fibroblasts. The combination of densely packed fibers and the paucity of cells characterizes dense connective tissue. Relatively few small blood vessels (BV) are shown on this section. x540.

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