 A top-down view of skeletal muscle A muscle fiber, also spelled muscle fibre (see spelling differences), also technically known as a myocyte, is a single cell of a muscle. Muscle fibers contain many myofibrils, the contractile unit of muscles. Muscle fibres are very long; a single fibre can reach a length of 30cm. Image File history File links Synapse_diag3. ...
Image File history File links Synapse_diag3. ...
An axon or nerve fiber, is a long, slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neurons cell body or soma. ...
A neuromuscular junction is the junction of the axon terminal of a motoneuron with the motor end plate, the highly-excitable region of muscle fiber plasma membrane responsible for initiation of action potentials across the muscles surface. ...
A diagram of the structure of a Myofybril Myofibrils (obsolete term: sarcostyles) are cylindrical organelles, found within muscle cells. ...
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American and British English spelling differences are one aspect of American and British English differences. ...
Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell. Cells in culture, stained for keratin (red) and DNA (green). ...
A top-down view of skeletal muscle Muscle (from Latin musculus little mouse [1]) is contractile tissue of the body and is derived from the mesodermal layer of embryonic germ cells. ...
A diagram of the structure of a Myofybril Myofibrils (obsolete term: sarcostyles) are cylindrical organelles, found within muscle cells. ...
A centimetre (American spelling centimeter, symbol cm) is a unit of length that is equal to one hundredth of a metre, the current SI base unit of length. ...
Muscle fibres can be grouped according to what kind of tissue they are found in -- skeletal muscle, smooth muscle, and cardiac muscle. The muscle cells of heart muscle tissue are called cardiomyocytes. Biological tissue is a collection of interconnected cells that perform a similar function within an organism. ...
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Cultured Smooth muscle of the aorta. ...
Cardiac muscle is a type of involuntary striated muscle found within the heart. ...
Skeletal muscle fibers
Skeletal muscle fibers can be further divided into two basic types, type I (slow-twitch fibers) and type II (fast-twitch fibers). Type II is further divided, as follows: This article or section does not cite any references or sources. ...
| type | Type I | Type IIa | Type IIb | | Description | slow oxidative (SO) fibers | fast oxidative-glycolytic (FOG) | fast-twitch glycolytic fibers | | myoglobin | high | medium | low | | mitochondria | many | moderate | few | | fatigues | slowly | moderate speed | fast | | color | red ("dark meat") | red | white ("white meat") | | diameter | narrow | medium | wide | Glycolysis is a metabolic pathway by which a molecule of glucose (Glc) is oxidized to two molecules of pyruvic acid (Pyr). ...
An X-ray diffraction image for the protein myoglobin. ...
In cell biology, a mitochondrion is an organelle found in the cells of most eukaryotes. ...
Type I Type I muscle fibers (slow-oxidative fibers) use primarily cellular respiration and, as a result, have relatively high endurance. Cellular respiration describes the metabolism reactions and processes that take place in a cell to obtain biochemical energy from fuel molecules. ...
To support their high-oxidative metabolism, these muscle fibers typically have lots of mitochondria and myoglobin, and thus appear red (what is typically termed "dark" meat in poultry.) Electron micrograph of a mitochondrion showing its mitochondrial matrix and membranes In cell biology, a mitochondrion (plural mitochondria) (from Greek μιτος or mitos, thread + χονδÏιον or khondrion, granule) is a membrane-enclosed organelle, found in most eukaryotic cells. ...
An X-ray diffraction image for the protein myoglobin. ...
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Type I muscle fibers are typically found in muscles of animals that require endurance, such as chicken leg muscles or the wing muscles of migrating birds (e.g., geese). This article or section does not adequately cite its references or sources. ...
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Type II Type II muscle fibers use primarily anaerobic metabolism and have relatively low endurance. These muscle fibers are typically used during tasks requiring short bursts of strength, such as sprints or weightlifting. Type II muscle fibers cannot sustain contractions for significant lengths of time, and are typically found in the white meat (e.g., the breast) of chicken. This article or section does not cite any references or sources. ...
Sprints are races where the runner tries to go as fast as humanly possible. ...
A weightlifter about to jerk 180 kg[1] Weightlifting is a sport in which competitors attempt to lift heavy weights mounted on steel bars called barbells, the execution of which is a combination of power, flexibility, technique, mental and physical strength. ...
There are two sub-classes of type II muscle fibers, type IIa (Fast-Oxidative) and IIb (Fast-Glycolytic).
- Type IIa (fast-oxidative) fibers also appear red, due to their high content of myoglobin and mitochondria.
- Type IIb (fast-glycolytic) are the fastest firing and most powerful, twitching in upwards of 120 times per second, are the fiber type of choice to a power lifter. They also tire the fastest. These fibers appear white histologically, due to their low oxidative demand, manifested by the lack of myoglobulin and mitochondria (relative to the Type I and Type IIa fibers).
Other terminology Most sources use the I/IIa/IIb division described above. However, this distinction is much more clear in other animals (such as chickens) than they are in humans, where the muscle tissue usually contains combinations of different kinds of fibers in varying proportions. This article or section does not adequately cite its references or sources. ...
Some terms used to describe this blending include:
- "Type III" or "Intermediate fast-twitch fibers" are a cross between Type I and Type IIb. They can utilize both aerobic and anaerobic pathways for energy metabolism.
- "Type IIc" fibers are created from a fusion of satellite cells to the corrupted Type IIb, so long as the cortisone hormone is inhibited, and offer the attributes of both Type IIa and Type IIb.
Cortisone (IPA:ˈkôrtəˌsÅn) is a steroid hormone. ...
See also In medicine, a myopathy is a neuromuscular disease in which the muscle fibers do not function for any one of many reasons, resulting in muscular weakness. ...
Myoblasts are a type of stem cells that exist in muscles. ...
External links | Histology: muscle tissue | | skeletal muscle/general | epimysium, fascicle, perimysium, endomysium, muscle fiber (intrafusal, extrafusal), myofibril sarcomere (a, i, and h bands; z and m lines), myofilaments (thin filament/actin, thick filament/myosin, elastic filament/titin, nebulin), tropomyosin, troponin (T, C, I) In 1828 the Medical Academy of Georgia was chartered by the state of Georgia with plans to offer a single course of lectures leading to a bachelors degree. ...
Duke University is a private coeducational research university located in Durham, North Carolina, USA. Founded by Methodists and Quakers in the present-day town of Trinity in 1838, the school moved to Durham in 1892. ...
The muscular system is the biological system of an organism that allows it to move. ...
A top-down view of skeletal muscle Muscle (from Latin musculus little mouse [1]) is contractile tissue of the body and is derived from the mesodermal layer of embryonic germ cells. ...
A top-down view of skeletal muscle A muscle contraction (also known as a muscle twitch or simply twitch) occurs when a muscle cell (called a muscle fiber) lengthens or shortens. ...
This is a list of muscles of the human anatomy. ...
A top-down view of skeletal muscle Muscle (from Latin musculus little mouse [1]) is contractile tissue of the body and is derived from the mesodermal layer of embryonic germ cells. ...
Cardiac muscle is a type of involuntary striated muscle found within the heart. ...
This article or section does not cite any references or sources. ...
Cultured Smooth muscle of the aorta. ...
A thin section of lung tissue stained with hematoxylin and eosin. ...
A top-down view of skeletal muscle Muscle (from Latin musculus little mouse [1]) is contractile tissue of the body and is derived from the mesodermal layer of embryonic germ cells. ...
This article or section does not cite any references or sources. ...
Epimysium is a layer of connective tissue which ensheaths the entire muscle. ...
In anatomy, a fascicle is a bundle of skeletal muscle fibers surrounded by connective tissue. ...
Perimysium is a sheath of connective tissue which groups individual muscle fibers ( anywhere between 10 to 100 or more) into bundles or fascicles Endomysium Histology at cytochemistry. ...
The endomysium, literally meaning within the muscle, is a layer of connective tissue that ensheaths a muscle fiber and is composed mostly from reticular fibers. ...
Intrafusal fibers are muscle fibers that comprise the muscle spindle. ...
Extrafusal muscle fibers are served by axons of the alpha motor neurons. ...
A diagram of the structure of a Myofybril Myofibrils (obsolete term: sarcostyles) are cylindrical organelles, found within muscle cells. ...
Image of sarcomere A sarcomere is the basic unit of a cross striated muscles myofibril. ...
See sarcomere. ...
G-Actin (PDB code: 1j6z). ...
Myosin is a motor protein filament found in muscle tissue. ...
Titin, also known as connectin, (UniProt name: Q10466_HUMAN; accession number: Q10466) is a protein that is important in the contraction of striated muscle tissues. ...
Nebulin is an actin-binding molecule which is localized to the I-band in skeletal muscle. ...
Troponin Tropomyosin, along with the troponin, regulate the shortening of the muscle protein filaments actin and myosin. ...
Troponin Troponin is a complex of three proteins that is integral to muscle contraction in skeletal and cardiac muscle, but not smooth muscle. ...
Troponin Troponin T is a part of the troponin complex. ...
Troponin Troponin C is a part of the troponin complex. ...
Troponin Troponin I is a part of the troponin complex. ...
costamere (dystrophin, α,β-dystrobrevin, syncoilin, synemin/desmuslin, dysbindin, sarcoglycan, dystroglycan, sarcospan), desmin The costamere is a structural-functional component of skeletal muscle cells which, according to original descriptions in the early 1980s (which are generally still accepted), are sub-sarcolemmal protein assemblies circumferentially aligned in register with the Z-disk of peripheral myofibrils. ...
Dystrophin is a protein found in membranes surrounding individual muscle fibers, and its deficiency is one of the root causes of muscular dystrophy. ...
Dystrobrevin is a protein that binds to dystrophin in the costamere of skeletal muscle cells. ...
Syncoilin is a muscle-specific intermediate filament, first isolated by Newey and colleagues[1] as a binding partner to α-dystrobrevin, as determined by a yeast two-hybrid assay. ...
Synemin, also called desmuslin, is an intermediate filament (IF) and, like other IFs, primarily functions to integrate mechanical stress and maintain structural integrity in eukaryotic cells. ...
Dysbindin, short for dystrobrevin-binding protein 1, is a protein constituent of the dystrophin-associated protein complex of skeletal muscle cells. ...
The sarcoglcyans are a family of five transmembrane proteins (α, β, γ, δ or ε) involved in the protein complex responsible for connecting the muscle fibre cytoskeleton to the extracellular matrix, preventing damage the muscle fibre sarcolemma through shearing forces. ...
Dystroglycan is a protein of the cytoskeleton involved in joining dystrophin and laminin. ...
Sarcospan, discovered by the research group of Kevin Campbell, is a 25-kDa transmembrane protein located in the dystrophin-associated protein complex of skeletal muscle cells. ...
Intermediate filaments are one component of the cytoskeleton - important structural components of living cells. ...
neuromuscular junction, motor unit, muscle spindle, excitation-contraction coupling, sliding filament mechanism A neuromuscular junction is the junction of the axon terminal of a motoneuron with the motor end plate, the highly-excitable region of muscle fiber plasma membrane responsible for initiation of action potentials across the muscles surface. ...
A motor unit is a group of cells under the control of a single motor neuron; groups of motor units work together, as a single muscle. ...
A muscle spindle is a specialized muscle structure innervated by both sensory and motor neuron axons. ...
// Excitation-contraction (EC) coupling is a term coined in 1952 to describe the physiological process of converting an electrical stimulus to mechanical response [1]. This process is fundamental to muscle physiology, whereby the electrical stimulus is usually an action potential and the mechanical response is contraction. ...
The sliding filament mechanism is a process used by muscles to contract. ...
myoblast, satellite cell, sarcoplasm, sarcolemma, sarcoplasmic reticulum, T-tubule | | cardiac muscle | myocardium, intercalated disc, nebulette | | smooth muscle | calmodulin, vascular smooth muscle | |
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