Athletes who are difficult to strain are prone to stress fractures.Revealed risk of genetic injury to female athletes
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Furthermore, as a result of detailed analysis of skeletal muscle, if type I collagen α1 chain gene polymorphism CC type or AC type is present, the bone density is low and the muscle is soft.
The research group of Assistant Professor Eri Miyamoto and Senior Associate Professor Noriyuki Fuku of Juntendo University Graduate School of Sport and Health Sciences will be held on April 4th ... → Continue reading
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Wikipedia related words
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Skeletal muscle is histologicallyStriated muscleAnd,Smooth muscleContrast with.However,Facial musclesSeen inRubber bandAndtongue,Pharynx,diaphragmAlthough part of the above does not support the skeleton, it is the striated muscle, which is a skeletal muscle tissue.
Each muscle fiber (also called muscle fiber) is one細胞And it is called a muscle cell.Many muscle cellsNuclearMultinucleated cells (Syncytia).A collection of muscle fibers constitutes a muscle bundle, and a collection of muscle bundles constitutes a skeletal muscle.
Arrangement and shape
Skeletal muscle骨 格AgainstjointIt is tied so as to straddle.From the relationship with the joints that are connected,FlexorとExtensorIt is divided into.The former is attached to the bending side of the joint, and the joint bends when it contracts.The latter is on the opposite side, and when it contracts, the joint stretches.Muscles exert strength when contracting, but they cannot stretch on their own, soFlexorとExtensorThe joints bend and stretch by acting antagonistically with each other.
Skeletal muscles vary in shape ...鋸筋Etc.
In addition, some skeletal muscles are branched and can be classified by the number of muscle heads (the part of the skeletal muscle near the center of the body).One with one muscle head, one with two muscle headsBiceps, Three thingsTriceps, Call four things.
Fast and slow muscle fibers
There are two main types of muscle fibers,MitochondriaRich inoxygenPossible continuous contraction using(Type 1, red streaks, color cause is oxygen bindingprotein,Myoglobin) And relatively few mitochondriaGlycolysisPossible instantaneous contraction due toIt can be divided into (Type 2, white streaks).Among the fast muscle fibers, those that are suitable for continuous contraction are further subdivided into Type 2a, and those that are not are further subdivided into Type 2X and Type 2b.Type 2b, the fastest fast muscle fiber, is contained in rodent skeletal muscle fibers such as rats, but is rarely contained in human skeletal muscle.
In addition, slow muscle fiber and fast muscle fiber are eachSlow muscle,Quick muscleOften called.Furthermore, it has both propertiesIntermediate muscleThe existence of is also recognized.
Nerves and sensory organs
Skeletal muscleMotor nervesIs dominated by the movementNerveWhen it receives a signal from, it contracts and exerts its power. Combine one motor nerve and the muscle fibers controlled by itMotor unitOrNeuromuscular unitCalled.The number of muscle fibers per motor nerve is small in muscles that make precise movements such as fingers, and large in muscles that make large movements such as the thighs.The nerve fibers that directly control the skeletal muscle fibers are α fibers.It has a large diameter (fast nerve conduction velocity).Also, for skeletal muscleMuscle spindle,Golgi tendon organと 呼 ば れ るSensory organExists.
- Muscle spindle
- Responds to changes in skeletal muscle length.The muscle spindle also consists of skeletal muscle fibers.This is the Ia group fiberと 呼 ば れ るsenseIn addition to nerves, it also controls nerve fibers called γ-motor nerves. γ-fibers regulate the sensitivity of the muscle spindle by contracting and relaxing the muscle spindle, and as a result, regulate the muscle tone state ().
- Golgi tendon organ
- It is located at the muscle-tendon junction and responds to skeletal muscle tension. Group Ib fiberIt leads to a nerve called.Tendon spindleAlso called.