Skeletal muscle

skeletal musclesskeletalmusclemuscle fibresmusclesmuscle fibersvoluntary muscleskeletal muscle cellsvoluntary musclesskeletal striated muscle
Skeletal muscle is one of three major muscle types, the others being cardiac muscle and smooth muscle.wikipedia
712 Related Articles

Cardiac muscle

myocardiumheart musclemyocardial
Skeletal muscle is one of three major muscle types, the others being cardiac muscle and smooth muscle.
Cardiac muscle (also called heart muscle or myocardium) is one of three types of vertebrate muscles, with the other two being skeletal and smooth muscles.

Muscle

musclesmuscularmusculature
Skeletal muscle is one of three major muscle types, the others being cardiac muscle and smooth muscle.
There are three types of muscle, skeletal or striated, cardiac, and smooth.

Somatic nervous system

somaticsomatomotorvoluntary nervous system
It is a form of striated muscle tissue, which is under the voluntary control of the somatic nervous system.
The somatic nervous system (SNS or voluntary nervous system) is the part of the peripheral nervous system associated with the voluntary control of body movements via skeletal muscles.

Muscle fascicle

fasciculifasciculusfascicles
A skeletal muscle refers to multiple bundles (fascicles) of cells joined together called muscle fibers.
A muscle fascicle is a bundle of skeletal muscle fibers surrounded by perimysium, a type of connective tissue.

Smooth muscle

smooth muscle cellssmooth musclessmooth muscle cell
Skeletal muscle is one of three major muscle types, the others being cardiac muscle and smooth muscle.
Smooth muscle is fundamentally different from skeletal muscle and cardiac muscle in terms of structure, function, regulation of contraction, and excitation-contraction coupling.

Myocyte

muscle fibermuscle cellmyoblast
Muscle fibres, or muscle cells, are formed from the fusion of developmental myoblasts in a process known as myogenesis.
There are various specialized forms of myocytes: cardiac, skeletal, and smooth muscle cells, with various properties.

Muscle contraction

contractionmuscular contractionexcitation-contraction coupling
The sarcomere is responsible for the striated appearance of skeletal muscle, and forms the basic machinery necessary for muscle contraction.
In vertebrates, skeletal muscle contractions are neurogenic as they require synaptic input from motor neurons to produce muscle contractions.

Sarcomere

sarcomeresZ-discZ-discs
The myofibrils are composed of actin and myosin filaments, repeated in units called sarcomeres, which are the basic functional units of the muscle fiber. In addition to the actin and myosin components that constitute the sarcomere, skeletal muscle fibers also contain two other important regulatory proteins, troponin and tropomyosin, that are necessary for muscle contraction to occur.
Skeletal muscles are composed of tubular muscle cells (myocytes called muscle fibers or myofibers) which are formed in a process known as myogenesis.

Myosatellite cell

satellite cellssatellite cellmuscle satellite cells
Another group of cells, the myosatellite cells are found between the basement membrane and the sarcolemma of muscle fibers.
Satellite cells are precursors to skeletal muscle cells, able to give rise to satellite cells or differentiated skeletal muscle cells.

Bone

bone tissuecancellous bonecortical bone
Most skeletal muscles are attached to bones by bundles of collagen fibers known as tendons.
They provide a frame to keep the body supported, and an attachment point for skeletal muscles, tendons, ligaments and joints, which function together to generate and transfer forces so that individual body parts or the whole body can be manipulated in three-dimensional space (the interaction between bone and muscle is studied in biomechanics).

T-tubule

transverse tubulestransverse tubuleT (transverse) tubules
T tubules are the pathways for action potentials to signal the sarcoplasmic reticulum to release calcium, causing a muscle contraction.
Transverse tubules (T-tubules) are extensions of the cell membrane that penetrate into the centre of skeletal and cardiac muscle cells.

Triad (anatomy)

triad
Together, two terminal cisternae and a transverse tubule form a triad.
In the histology of skeletal muscle, a triad is the structure formed by a T tubule with a sarcoplasmic reticulum (SR) known as the terminal cisterna on either side.

Myogenesis

muscle differentiationmyotubesmyoblast fusion
Muscle fibres, or muscle cells, are formed from the fusion of developmental myoblasts in a process known as myogenesis.
Consequently, the simultaneous deletion of Myf5 and MyoD also results in a complete lack of skeletal muscle formation.

Myofibril

myofibrilsactomyosinmyofibrillar
Muscle fibers are in turn composed of myofibrils.
In striated muscle, such as skeletal and cardiac muscle, the actin and myosin filaments each have a specific and constant length on the order of a few micrometers, far less than the length of the elongated muscle cell (a few millimeters in the case of human skeletal muscle cells).

Striated muscle tissue

striated musclestriationsstriated muscles
It is a form of striated muscle tissue, which is under the voluntary control of the somatic nervous system.
Skeletal muscle

Troponin

troponin complexcardiac troponinstroponin test
In addition to the actin and myosin components that constitute the sarcomere, skeletal muscle fibers also contain two other important regulatory proteins, troponin and tropomyosin, that are necessary for muscle contraction to occur.
Troponin, or the troponin complex, is a complex of three regulatory proteins (troponin C, troponin I, and troponin T) that is integral to muscle contraction in skeletal muscle and cardiac muscle, but not smooth muscle.

Sarcoplasmic reticulum

sarcoplasmicsarcosarcoplasmic reticulum (SR)
While the muscle fiber does not have a smooth endoplasmic cisternae, it contains a sarcoplasmic reticulum.
These processes are explained in more detail below and are fundamental for the process of excitation-contraction coupling in skeletal, cardiac and smooth muscle.

Anatomical terms of muscle

antagonistagonistinsertion
Antagonism in the transmission of nerve impulses to the muscles means that it is impossible to fully stimulate the contraction of two antagonistic muscles at any one time.
Skeletal striated muscle, or "voluntary muscle", primarily joins to bone with tendons.

Actin

alpha-actinF-actinthin filament
The myofibrils are composed of actin and myosin filaments, repeated in units called sarcomeres, which are the basic functional units of the muscle fiber. In addition to the actin and myosin components that constitute the sarcomere, skeletal muscle fibers also contain two other important regulatory proteins, troponin and tropomyosin, that are necessary for muscle contraction to occur.
Of these, two code for the cytoskeleton (ACTB and ACTG1) while the other four are involved in skeletal striated muscle (ACTA1), smooth muscle tissue (ACTA2), intestinal muscles (ACTG2) and cardiac muscle (ACTC1).

Cell nucleus

nucleusnucleinuclear
Muscle fibres are cylindrical, and have more than one nucleus.
In humans, skeletal muscle cells, called myocytes and syncytium, become multinucleated during development; the resulting arrangement of nuclei near the periphery of the cells allows maximal intracellular space for myofibrils.

Pennate muscle

pennatepennate musclespennation
The different fiber arrangements produce broad categories of skeletal muscle architectures including longitudinal, pennate, unipennate, bipennate, and multipennate.
Namely, the maximum (tetanic) force of a muscle fiber simply depends on its thickness (cross-section area) and type.

Calmodulin

calcium/calmodulincalcium/calmodulin (Ca2+/CaM)CaM
Calcineurin, a Ca2+/calmodulin-activated phosphatase implicated in nerve activity-dependent fiber-type specification in skeletal muscle, directly controls the phosphorylation state of the transcription factor NFAT, allowing for its translocation to the nucleus and leading to the activation of slow-type muscle proteins in cooperation with myocyte enhancer factor 2 (MEF2) proteins and other regulatory proteins.
Troponin C has a very specific function (to elicit a conformational change in Troponin I) ultimately causing a contraction in skeletal muscles.

Acetylcholine

cholinergicacetylcholine (ACh)ACh
Skeletal muscle cells are excitable and are subject to depolarization by the neurotransmitter acetylcholine, released at the neuromuscular junction by motor neurons.
Acetylcholine is the substance the nervous system uses to activate skeletal muscles, a kind of striated muscle.

Electromyography

EMGelectromyogramelectromyographic
The electrical activity associated with muscle contraction are measured via electromyography (EMG).
Electromyography (EMG) is an electrodiagnostic medicine technique for evaluating and recording the electrical activity produced by skeletal muscles.

Epimysium

epimysia
Enclosing each muscle is a layer of connective tissue known as the epimysium; enclosing each fascicle is a layer called the perimysium, and enclosing each muscle fiber is a layer of connective tissue called the endomysium.
Connective tissue in skeletal muscle