Composed of different types of elongated multinucleated myofibers.
Has a vital role in regulating immune function, glucose disposal, protein synthesis, and mobility.
Skeletal muscle cells can modify immune response through muscle cell derive cytokines (myokines), cell surface molecules, and cell to cell interactions, which alter T sell homeostasis.
Skeletal muscles make up 40% of the body mass.
Contributes the largest body stores of proteins, minerals and other intermediate metabolites that can be disassembled to meet the needs of other tissues involved in the inflammatory response to fight against illnesses.
Progressive reduction in muscle mass and strength that occurs with aging limits mobility.
Type 1 myofibers have slow twitch speed of contraction, marked oxidative capacity and red appearance.
Type 2 myofibers have faster twitch speed of contraction, oxidative and glycotic metabolism and are fairly white in appearance.
Very adaptable and can change metabolic and contractile properties of myofibers in response to exercise.
Aerobic exercise allows myofibers to take on slow twitch phenotype with increased levels of oxidative enzymes, glycogen and glucose transporter-4.
Muscle tissue is three times more efficient at burning calories than fat.
Two types of muscle unit Type 1 an Type 2.
Type 1 muscles have small cell diameter and high excitability with moderate conduction velocity and low fatigability.
Type 2 muscle fibers are large cell diameter with low excitability, very fast conduction velocity and high fatigability.
Type 1 muscle fibers have an oxidative profile.
Type 2 muscle fibers have a glycolytic profile.
Type 1 fibers are few in number and Type 2 fibers are numerous in quantity.
Type 1 fibers, the small motor unit, are recruited first and are active while the Type 2, large motor unit, fibers are unused infrequently in forceful contractions.
Maximal effort recruits Type 2 fast fibers but can not sustain activity because of the depletion of glycogen.
Aerobic exercising increases insulin sensitivity of muscle and improvement in glucose homeostasis.
Inactivity may cause the conversion of myofibers to convert to the fast switch phenotype, making such fibers less able to perform sustained aerobic and contributing to an insulin resistant state.
Skeletal muscle weakness is a phenotype of frailty and is strongly associated with physical disabilities and reduced exercise capacity.
Skeletal muscle strength is a prognostic factor in community dwellers, and chronic heart failure.
There is increased mortality rate and hospital length of stay among patients with low muscle mass.
Most of these muscles move the skeleton and are attached to bone or cartilage either directly or by tendons.
Muscles not attached to the skeleton include eye muscles, facial muscles and the diaphragm.
Called striated muscle because of the presence of parallel striations that are unbranched and may contain multiple nuclei.
Innervated with nerves from the somatic nervous system.
Aerobic exercising increases insulin sensitivity of muscle and improvement in glucose homeostasis.
Inactivity may cause the conversion of myofibers to convert to the fast switch phenotype, making such fibers less able to perform sustained aerobic and contributing to an insulin resistant state.
There is a poor association between BMI and muscle mass due to lack of discrimination among lean, fat, and water body mass.
Genetic muscle wasting disorders lead to loss of voluntary movement, comprised quality of life, and premature death.
Abnormal, skeletal muscle measurements at baseline, such as low muscle mass and resultant fat infiltration is associated with adverse cancer related outcomes, and all cause mortality in patients with solid and hematologic malignanciess, including those undergoing hematopoetic stem cell transplant.