Muscle contraction is the process in which the energy from chemical reactions in the muscle can be converted into useful work or force. This process of muscle contraction allows us to move around and perform immediate actions. There is a vast variety of muscles that are found in the different bodies of animals, and each muscle structure is uniquely fit for its specific role. However, it seems that the many diverse muscles all have the same contractile process. The many different muscles rely on actin and myosin, the proteins in the muscle that are responsible for movement, to interact with the splitting of adenosine triphosphate (ATP) to form adenosine diphosphate (ADP). Chemical reactions supply the energy for muscle contraction, and blood circulation is the transportation of the fuel for these reactions to the muscles.
The body’s movements are produced by the contraction of cardiac and smooth muscle. The heart consists mainly of cardiac muscle which is self-contracting and autonomically regulated. This rhythmic pattern of contraction is an intrinsic or exclusive characteristic of the cardiac muscle tissue. Signals from the nervous system can modify the contractions but are not necessary for the constant rhythmic fashion to continue during the whole life of the organism. Smooth muscle is responsible for the contraction of organs like the blood vessels, the gastrointestinal tract, the bladder, or the uterus.
Motion of the full body is produced by the cooperation among the skeletal muscles and other systems, including skeletal, nervous, and circulatory systems. A skeletal muscle consists of muscle fibers of which muscle contraction can cause only a pulling action, so any movement of the body would require a muscle to bend a joint and another muscle to straighten it out. Movements of the body tend to involve the action of many muscles of which the actions are all controlled by the nervous system. This can be performed by coordinating the signals of both the brain and spinal cord in the form of action potential that are sent to the muscles. When an electrical signal crosses the “neuromuscular junction”, the place where the nerve and muscle meet, it is transmitted deep inside the muscle fibers. The signal will stimulate the flow of calcium which will cause the filaments to not change in length during contraction but instead cause the thin filaments to slide over the thick filaments. Once this
