Muscle (Myofibrillar Ultrastructural Structure and Contractile Efficiency) is a specialized contractile tissue in the bodies of vertebrates that is responsible for the generation of movement. Muscle fibers are composed of myofibrils, which are composed of actin and myosin proteins. These proteins interact to produce contractions, allowing muscle fibers to move in response to electrical signals from the nervous system. This paper will review the structure and function of muscle, its role in locomotion, and the biochemical and biomechanical processes involved in muscle contraction.

The structure of muscle is composed of several components. The most prominent are the myofibrils, which are made of thick and thin filaments composed of actin and myosin proteins. These filaments are arranged in a repeating pattern known as a sarcomere. The sarcomere is the basic structural and functional unit of muscle fibers, and its organization is essential for efficient muscle contraction. In addition to the myofibrils, muscle fibers also contain several accessory structures, such as mitochondria, sarcoplasmic reticulum, and connective tissue.

Muscle fibers are specialized for the production of force and movement. When an electrical signal, known as an action potential, is passed along a muscle fiber, this triggers a series of biochemical and biomechanical processes that result in muscle contraction. The most important of these processes is the sliding filament theory, which describes how the actin and myosin proteins interact to produce force and movement. The sliding filament theory is based on the fact that actin and myosin proteins are arranged in such a way that when an action potential is passed along a muscle fiber, the myosin proteins attach to the actin filaments and pull them inwards, resulting in muscle contraction.

Muscle is essential for the production of movement in the body. It is responsible for locomotion, posture maintenance, and other activities of daily living. In addition, muscle plays a role in the regulation of body temperature, blood pressure, and other physiological processes. Muscle contraction requires the coordination of several different processes, including nerve conduction, metabolic activity, and the production of force.

In conclusion, muscle is a specialized tissue that is essential for the production of movement and other physiological processes in the body. It is composed of several different components, including myofibrils, accessory structures, and biochemical and biomechanical processes. The coordination of these processes is essential for the efficient production of force and movement.


Hill, A.V. (1938). Muscular contraction. Proceedings of the Royal Society of London. Series B, Biological Sciences, 126(825), 136-195.

Olivé, M. (2020). Biomechanics of muscle contraction. Physiological Reviews, 100(4), 1699-1767.

Sarcomere. (2020). In Encyclopedia Britannica. Retrieved from

Sliding filament theory. (2020). In Encyclopedia Britannica. Retrieved from

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