What is the contraction of the skeletal muscle?

The contraction of the skeletal muscle is the mechanism by which the muscles of the moving joints of the body create movement in these joints. The skeletal muscle is distinguished from the heart muscle that pumps the heart and smooth muscles, which is part of several internal organs and produces movements such as pushing food along the digestive tract, and at both ends it is associated with bone. As such, when it downloads - that is, when its fibers are shortened and extended - it attracts two bones and causes movement on the joint that intersects. The contraction of the skeletal muscle, which includes a chemical reaction to the level of protein components contained in each muscle cell, is what allows the skeleton to move. The contraction in which the muscle fibers are shortened, as can be seen when the thoracic cage is attracted closer to the pelvis during the abdominal crisis is called concentric contraction. When muscle fibers extend, as well as the crisis reducing phase, eccentric contraction occurs. Skeletal muscle contraction including concentric and eccentric fThe movement is known as isotonic contraction. On the other hand, there is an isometric contraction in which the muscle does not change when closing the muscles, as in holding the position of squat without movement.

skeletal muscle is made up of muscle fiber bundles, which in turn are bundles of muscle cells. Muscle cells are long, narrow and cylindrical shape and consist of units called saromers that are responsible for the contraction of the skeletal muscle. The model that explains what is happening in sarcomers as muscle contracts is called the theory of sliding fibers. It can be used to explain all types of muscle contraction, which differ only as a result of whether the force applied to the muscles is less, greater than or equal to the strength produced by muscle cells.

in each sarcomer, a unit found in hundreds of thousands in each muscle cell, proteins are organized in long fibers called actin and myosin. Actin proteins are passiveIt means that they create chains that receive active proteins of myosin. Myosin, arranged in alternating lines, slips back and forth around the actin, and in the process it emits calcium ions that cause every myosin protein to bind to the corresponding location at any actin protein.

During the contraction of the skeletal muscle, myosin fibers are caught and stretched. This occurs at the same time in many sarcomers of the cells that are arranged in the bands. This "stroke", as is commonly known, causes a collective shortening of muscle, which then returns to its resting length when myosin is released from the actin.