Most groups of skeletal muscle fibers of the body are organized into bundles of different complexity levels.
A small amount of loose connective tissue is placed between the muscle fibers called the endomysium (in red in the drawing and highlighted in the image of the histological section). This connective tissue contains the blood vessels, lymphatic vessels, and nerves that nourish and innervate the cells.
A layer of dense connective tissue called perimysium surrounds bundles muscle fibers (in green in the drawing and highlighted in the section).
The whole muscle is surrounded by a layer of dense, regular connective tissue, called epimysium (in pink in the drawing).
The lower image shows a cross-section of skeletal muscle stained with a trichrome dye that helps to distinguish connective tissue.
Skeletal muscle. Staining: Masson’s trichrome. Small magnification.
