Skeletal muscle structure and function – Musculoskeletal GeneticsMuscle is a soft tissue found in most animals. Muscle cells contain protein filaments of actin and myosin that slide past one another, producing a contraction that changes both the length and the shape of the cell. Muscles function to produce force and motion. They are primarily responsible for maintaining and changing posture , locomotion , as well as movement of internal organs , such as the contraction of the heart and the movement of food through the digestive system via peristalsis. Muscle tissues are derived from the mesodermal layer of embryonic germ cells in a process known as myogenesis. There are three types of muscle, skeletal or striated, cardiac , and smooth. Muscle action can be classified as being either voluntary or involuntary.
Structure of Skeletal Muscle
The skeletal muscle extracellular matrix ECM plays an important role in muscle fiber force transmission, maintenance, and repair. In both injured and diseased states, ECM adapts dramatically, a property thathas clinical manifestations and alters muscle function. Here, we review the structure, composition, and mechanical properties of skeletal muscle ECM, describe the cells that contribute to the maintenance of the ECM and, finally, overview changes that occur with pathology. New scanning electron micrographs of ECM structure are also presented with hypotheses about ECM structure-function relationships. Detailed structure-function relationships of the ECM have yet to be defined and, as a result, we propose areas for future studies. Skeletal muscles are composed primarily of contractile material.
The muscle system is responsible for movement of the human body, posture, movement of substances inside the body andfor the generation of body heat. There are approximately known and named muscles and on top of that, muscle tissue is also found inside of the heart, digestive organs, and blood vessels. Skeletal muscle is a voluntary muscle, which means that we can actively control its function. Skeletal muscles often exist in pairs, whereby one muscle is the primary mover and the other acts as an antagonist. For example when you bend your arm, your biceps contracts whilst your triceps is relaxed. When your arm returns to the extended position it is the triceps that contracts and the biceps relaxes. Skeletal muscle is a fascinating tissue with a complex structure.
A whole skeletal muscle is considered an organ of the muscular system. Each organ or muscle consists of skeletal muscle tissue , connective tissue , nerve tissue , and blood or vascular tissue. Skeletal muscles vary considerably in size, shape, and arrangement of fibers. They range from extremely tiny strands such as the stapedium muscle of the middle ear to large masses such as the muscles of the thigh. Some skeletal muscles are broad in shape and some narrow. In some muscles the fibers are parallel to the long axis of the muscle; in some they converge to a narrow attachment; and in some they are oblique.