Skeletal Muscle

Original Editor - Lucinda hampton

Top Contributors - Lucinda hampton  

Introduction

Fascia surrounding muscle fibre

Skeletal muscle attaches to the bone by tendons, and together they produce all body movements. However it has important roles in health beyond voluntary movement. Human skeletal muscle is an extremely dynamic and responsive tissue. Humans skeletal muscle constitutes roughly 40% of total body weight and a huge 50-75% of all the bodies proteins. Our muscle mass muscle mass depends on the dynamic process of protein synthesis and loss, this activity being responsive to factors including nutritional status, hormonal balance, physical activity/exercise, and injury or disease. As such it has important roles in health beyond voluntary movement.

Skeletal muscle fibers are crossed with a orderly pattern of fine red and white lines, hence its name striated muscle. For more on anatomical structure see Muscle Cells (Myocyte)

Biomechanical Organ

Muscle plays a large part in whole-body protein metabolism by acting as the primary reservoir for amino acids to keep protein synthesis occurring in vital tissues and organs when amino acid absorption is not inadequate from gut absoption and by providing hepatic gluconeogenic precursors. Altered muscle metabolism has a large role in the genesis of many common pathologic conditions and chronic diseases.

Muscle can be viewed as a biomechanical organ requiring the coordination between diverse factors both intrinsic (e.g., genetic) and extrinsic (e.g., environmental stressors, circulatory factors, etc.) to function normally. Abnormal molecular mechanisms can lead to disease and muscle research at many levels (genomic, molecular and mechanistic) is helping in the prevention and management of skeletal muscle health and disease.

Immune Function

Research shows the importance of regular exercise and physical activity by boosting the body’s capacity to fight opportunist infections, and as a "medicine" to fight established diseases. This interaction is credited to glutamine, a non-essential amino acid made by the active skeletal muscle and used by rapidly dividing cells, including lymphocytes and monocytes/macrophages, as their main source of energy.

Endocrine Organ

Skeletal muscle is now identified as an endocrine organ. Skeletal muscle releases myokines, which have the ability to regulate some physiological processes. Additionally skeletal muscle plays a large role in maintaining body homeostasis as it is responsible for greater than 3/4's of all insulin-mediated glucose use. Changes that may occur in skeletal muscle differentiation and function cause dysfunctional expression and secretion of myokines. These altered myokines contribute to the pathogenesis of obesity, type 2 diabetes, and other metabolic diseases.

Abnormalities

Many medical conditions occur due to abnormalities in skeletal muscles' function.

• These include myopathy, paralysis eg spinal cord injury, myasthenia gravis, urinary and/or bowel incontinence, ataxia, weakness, tremors, and others.
• Neuronal disorders can cause neuropathy and cause alterations in skeletal muscles function.
• Skeletal muscle/tendon ruptures also occur acutely and cause serious disability in patients regardless of how active they are.