Connective Tissue

An individual skeletal muscle is separated from adjacent muscles and held in place by layers of fibrous connective tissues call "fascia." This connective tissue surrounds each muscle and may project beyond the end of its muscle fibers to form a cordlike "tendon". Fibers in a tendon intertwine to attach the fibers of the muscle to the bone. In other cases, the fascia associated with a muscle may form broad, fibrous sheets called "aponeuroses," which may be attached to the coverings of the adjacent muscles. The layer of fascia that closely surrounds a skeletal muscle is called the "epimysium". Other layers of fascia, called the "perimysium," extend inward from the skeletal muscle and separate the tissue into small compartments which contain bundles of bones muscle fibers called "fascicles". Each muscle fiber within a fascicle is surrounded by a layer of fascia in the form of a thin, delicate covering; so, all parts of a skeletal muscle are wrapped in layers of fascia, allowing the parts to have independent movement. Many nerves and blood vessels pass through the layers as well. A skeletal muscle fiber represents one single cell of muscle. This fiber responds to stimulation and when it responds, it contracts and relaxes. Each skeletal muscle fiber is a thin, longish cylinder with rounded ends that are attached to fascia relative to the muscle. Just beneath the cell membrane or "sarcolemma," the fiber contains many threadlike "myofibrils" that lie along side each other and play a fundamental role in the process of muscle contraction. The fascia associated with the individual organs of the muscular system are part of a complete network of fascia that extends throughout the body. The part of this network that surrounds and penetrates the muscles is called "deep fascia." It is continuous with the "subcutaneous fascia" that forms the fascia covering organs in various body cavities as well as the cavities themselves.