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Muscle atrophy is the loss of skeletal muscle mass. It can be caused by immobility, aging, malnutrition, medications, or a wide range of injuries or diseases that impact the musculoskeletal or nervous system. Muscle atrophy leads to muscle weakness and causes disability.
Symptoms of neuromuscular disease may include numbness, paresthesia, muscle atrophy, a pseudoathletic appearance, exercise intolerance, myalgia (muscle pain), fasciculations (muscle twitches), myotonia (delayed muscle relaxation), hypotonia (lack of resistance to passive movement), fixed muscle weakness (a static symptom), or premature muscle ...
There are many proposed causes of sarcopenia and it is likely the result of multiple interacting factors. Understanding of the causes of sarcopenia is incomplete, however changes in hormones, immobility, age-related muscle changes, nutrition and neurodegenerative changes have all been recognized as potential causative factors.
The causes are many and can be divided into conditions that have true or perceived muscle weakness. True muscle weakness is a primary symptom of a variety of skeletal muscle diseases, including muscular dystrophy and inflammatory myopathy. It occurs in neuromuscular junction disorders, such as myasthenia gravis. [citation needed]
A smaller temporalis muscle can actually indicate sarcopenia, which is the age-related loss of muscle mass and strength. “Systemic sarcopenia “is often linked to frailty, reduced mobility, and ...
A sarcomere (Greek σάρξ sarx "flesh", μέρος meros "part") is the smallest functional unit of striated muscle tissue. [1] It is the repeating unit between two Z-lines. Skeletal muscles are composed of tubular muscle cells (called muscle fibers or myofibers) which are formed during embryonic myogenesis.
The muscle protein, dystrophin, is in most muscle cells and works to strengthen the muscle fibers and protect them from injury as muscles contract and relax. [3] It links the muscle membrane to the thin muscular filaments within the cell. Dystrophin is an integral part of the muscular structure.
Necrotic muscle fibers are swollen and eosinophilic and lack striations and nuclei. Small-vessel walls are thickened and hyalinized , with luminal narrowing or complete occlusion. Biopsy cultures for bacteria , fungi , acid-fast bacilli and stains are negative in simple myonecrosis.