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Muscle structure
The muscles in the human body that are connected to bones and aid in the movement of the skeleton are called skeletal muscles.
These muscles are connected to bones by tendons. Within each of the skeletal muscles are bundles of muscle fibers.
These bundles are also called fascicles.
Each skeletal muscle fiber contains many myofibrils which are rod-shaped and contains many sarcomeres (the functioning unit of muscle tissue.)
Sarcomeres are made up of thin filaments (composed mainly of the protein actin) and thick filaments (composed mainly of the protein myosin)
The actin of the outermost myofibril is connected to the cell membrane by a protein called dystrophin.
Explanation:
The skeletal muscles vary in shape, size and arrangement of the muscle fibers. Each muscle fiber in itself is a single cell of muscle which are all connected together to form the bundle of muscle fibers which are covered by connective sheath (epimysium).
These bundles called the fasciles are further surrounded by perimysium and endomysium which all act as protective layers and allows blood and nerves to pass through the muscle cells.
The myofibrils contain the sarcomeres, which are the main functional units of muscles.
Sarcomeres activate muscle contraction with the contractile action of their myofilaments. The myofilaments can be thin (made up of protein actin) or thick filaments (myosin).
The protein dystrophin present on the outer layers of muscle fibers works together with actin and aids in muscle contraction and strengthening.
