The muscular system controls numerous functions, which is possible with the significant differentiation of muscle tissue morphology and ability.
The muscular system is made up of muscle tissue and is responsible for functions such as maintenance of posture, locomotion and control of various circulatory systems. This includes the beating of the heart and the movement of food through the digestive system. The muscular system is closely associated with the skeletal system in facilitating movement. Both voluntary and involuntary muscular system functions are controlled by the nervous system.
Muscle is a highly-specialized soft tissue that produces tension which results in the generation of force. Muscle cells, or myocytes, contain myofibrils comprised of actin and myosin myofilaments which slide past each other producing tension that changes the shape of the myocyte. Numerous myocytes make up muscle tissue and the controlled production of tension in these cells can generate significant force.
Muscle tissue can be classified functionally as voluntary or involuntary, and morphologically as striated or non-striated. Voluntary refers to whether the muscle is under conscious control, while striation refers to the presence of visible banding within myocytes caused by the organization of myofibrils to produce constant tension.
Key Points
• The muscular system is responsible for functions such as maintenance of posture, locomotion, and control of various circulatory systems.
• Muscle tissue can be divided functionally (voluntarily or involuntarily controlled) and morphologically (striated or non-striated).
Key Terms
Musculoskeletal system: An organ system made up of the muscular and skeletal systems; the system provides form, support, stability, and movement to the body.
Myocytes: A muscle cell.
Actin: A protein that forms (together with myosin) the contractile filaments of muscle cells, and is also involved in motion in other types of cells.
Myosin: A fibrous protein that forms (together with actin) the contractile filaments of muscle cells and is also involved in motion in other types of cells.
Myofilments: Myofilaments are the filaments of myofibrils, constructed from proteins, principally myosin or actin.
Voluntary muscle: Muscle that is under the control of the will and is generally attached to the skeleton.
Involuntary muscle: A muscle that contracts without conscious control and found in walls of internal organs such as stomach and intestine and bladder and blood vessels (excluding the heart).
Striated muscle: Muscle tissue in which the contractile fibrils in the cells are aligned in parallel bundles, so that their different regions form stripes visible in a microscope. Muscles of this type are attached to the skeleton by tendons and are under voluntary control
Non-striated muscle: Smooth, thin muscle that isn’t controlled voluntarily.