The broad sheet of connective tissue in the lower back that the latissimus dorsi muscles (the “lats”) fuse into is an example of an aponeurosis.Įvery skeletal muscle is also richly supplied by blood vessels for nourishment, oxygen delivery, and waste removal. In other places, the mysia may fuse with a broad, tendon-like sheet called an aponeurosis, or to fascia, the connective tissue between skin and bones. The tension created by contraction of the muscle fibers is then transferred though the mysia, to the tendon, and then to the periosteum to pull on the bone for movement of the skeleton. At the other end of the tendon, it fuses with the periosteum coating the bone. In skeletal muscles that work with tendons to pull on bones, the collagen in the three tissue layers (the mysia) intertwines with the collagen of a tendon. Muscle fibers are covered by the endomysium. Bundles of muscle fibers, called fascicles, are covered by the perimysium. These nutrients are supplied via blood to the muscle tissue.įigure 1. The Three Connective Tissue Layers. The endomysium contains the extracellular fluid and nutrients to support the muscle fiber. Inside each fascicle, each muscle fiber is encased in a thin connective tissue layer of collagen and reticular fibers called the endomysium. This fascicular organization is common in muscles of the limbs it allows the nervous system to trigger a specific movement of a muscle by activating a subset of muscle fibers within a bundle, or fascicle of the muscle. Inside each skeletal muscle, muscle fibers are organized into individual bundles, each called a fascicle, by a middle layer of connective tissue called the perimysium. The epimysium also separates muscle from other tissues and organs in the area, allowing the muscle to move independently. Each muscle is wrapped in a sheath of dense, irregular connective tissue called the epimysium, which allows a muscle to contract and move powerfully while maintaining its structural integrity. Each skeletal muscle has three layers of connective tissue (called “mysia”) that enclose it and provide structure to the muscle as a whole, and also compartmentalize the muscle fibers within the muscle (Figure 1). These tissues include the skeletal muscle fibers, blood vessels, nerve fibers, and connective tissue. Skeletal Muscle Structure:Įach skeletal muscle is an organ that consists of various integrated tissues. This heat is very noticeable during exercise, when sustained muscle movement causes body temperature to rise, and in cases of extreme cold, when shivering produces random skeletal muscle contractions to generate heat. Muscle contraction requires energy, and when ATP is broken down, heat is produced. Skeletal muscles contribute to the maintenance of homeostasis in the body by generating heat. Skeletal muscles also protect internal organs (particularly abdominal and pelvic organs) by acting as an external barrier or shield to external trauma and by supporting the weight of the organs. These muscles allow functions, such as swallowing, urination, and defecation, to be under voluntary control. Skeletal muscles are located throughout the body at the openings of internal tracts to control the movement of various substances. Joints can become misaligned or dislocated entirely by pulling on the associated bones muscles work to keep joints stable. Muscles also prevent excess movement of the bones and joints, maintaining skeletal stability and preventing skeletal structure damage or deformation. Small, constant adjustments of the skeletal muscles are needed to hold a body upright or balanced in any position. Skeletal muscles act not only to produce movement but also to stop movement, such as resisting gravity to maintain posture. Skeletal muscle tissue forms skeletal muscles. The best-known feature of skeletal muscle is its ability to contract and cause movement.
0 Comments
Leave a Reply. |