There's also trace minerals that act as electrolytes, which help with nerve conduction, they help with brain function, they help with muscular contraction.
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When an antagonistic muscular contraction does occur during stage 2, the fish rotates in the opposite direction, producing a counter-turn, and a directional change.
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There is some pigmentation around the body and it is horizontally segmented. The legs are short and do not help much in locomotion. They move mostly through muscular contraction.
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Beress, L., and R. Beress. "Reinigung zweier krabbenlähmender Toxine aus der Seeanemone Anemonia sulcata." Kieler Meeresforsch 27 (1971): 117-127. Toxin III has been shown to cause muscular contraction with subsequent paralysis in the crab Carcinus maenas.
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Reich argues that character structures were organizations of resistance with which individuals avoided facing their neuroses: different character structures — whether schizoid, oral, psychopathic, masochistic, hysterical, compulsive, narcissistic, or rigid — were sustained biologically as body types by unconscious muscular contraction.
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Bennett was born in Philadelphia. He invented an extensive exercise regime of self-care that involved muscular contraction and relaxation exercises for rejuvenating the body.Stark, James F. (2018). Replace them by Salads and Vegetables: Dietary Innovation, Youthfulness, and Authority, 1900–1939.
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However, trills may also be produced with only one contact. While single- contact trills are similar to taps and flaps, a tap or flap differs from a trill in that it is made by a muscular contraction rather than airstream.
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Like tendons, aponeuroses attached to pennate muscles can be stretched by the forces of muscular contraction, absorbing energy like a spring and returning it when they recoil to unloaded conditions. Also serving as an origin or insertion site for certain muscles e.g latissimus dorsi.
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The bell margin is ringed with the muscular velum, which is typical of hydromedusae, and aids in locomotion through muscular contraction of the bell. Larger specimens are frequently found with symbiotic hyperiid amphipods attached to the subumbrella, or even occasionally living inside the gut or radial canals.
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The muscular contraction of arterioles is targeted by drugs that lower blood pressure (antihypertensives), for example the dihydropyridines (nifedipine and nicardipine), which block the calcium conductance in the muscular layer of the arterioles, causing relaxation. This decreases the resistance to flow into peripheral vascular beds, lowering overall systemic pressure.
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The ventricular myocardial band model supports the existence of an active muscular contraction that creates suction (creation of suction in diastole is extremely problematic with current theory) during ventricular diastole. Thus, it is the contraction of the ascending segment of the myocardial band that paradoxically increases the ventricular volume.
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Those who think that the major part of the respiratory changes are pre-programmed in the brain, which would imply that neurons from locomotion centers of the brain connect to respiratory centers in anticipation of movements. 2\. Those who think that the major part of the respiratory changes result from the detection of muscle contraction, and that respiration is adapted as a consequence of muscular contraction and oxygen consumption. This would imply that the brain possesses some kind of detection mechanisms that would trigger a respiratory response when muscular contraction occurs. Many now agree that both mechanisms are probably present and complementary, or working alongside a mechanism that can detect changes in oxygen and/or carbon dioxide blood saturation.
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Béclard was the author of a classic work on human physiology called Traité élémentaire de physiologie humaine comprenant les principales notions de la physiologie comparée (1856). Another noted work of his was Contraction musculaire dans ses rapports avec la température animale, a treatise involving correlation of muscular contraction to temperature.
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The crus of diaphragm (pl. crura), refers to one of two tendinous structures that extends below the diaphragm to the vertebral column. There is a right crus and a left crus, which together form a tether for muscular contraction. They take their name from their leg-shaped appearance – crus meaning leg in Latin.
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The sensory receptors for this reflex are called tendon Golgi receptors, which lie within a tendon near its junction with a muscle. In contrast to muscle spindles, which are sensitive to changes in muscle length, tendon organs detect and respond to changes in muscle tension that are caused by muscular contraction, but not passive stretch.
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This ridge is called a 'keel'. Foot The bottom side of a slug, which is flat, is called the 'foot'. Like almost all gastropods, a slug moves by rhythmic waves of muscular contraction on the underside of its foot. It simultaneously secretes a layer of mucus that it travels on, which helps prevent damage to the foot tissues.
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An inotrope is an agent that alters the force or energy of muscular contractions. Negatively inotropic agents weaken the force of muscular contractions. Positively inotropic agents increase the strength of muscular contraction. The term inotropic state is most commonly used in reference to various drugs that affect the strength of contraction of heart muscle (myocardial contractility).
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Langrish published A New Essay on Muscular Motion (1733) in which the structure of muscles and the phenomena of muscular contraction were discussed. In 1735 he published The Modern Theory and Practice of Physic, including original clinical. He described experiments in the analysis of excreta and the examination of the blood. A second edition appeared in 1764.
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Waldrop, Iwamoto and Haouzi, 2006 The authors can be classified in 2 schools: #Those who think that the major part of the respiratory changes are pre-programmed in the brain, which would imply that neurons from locomotion centers of the brain connect to respiratory centers in anticipation of movements. #Those who think that the major part of the respiratory changes result from the detection of muscle contraction, and that respiration is adapted as a consequence of muscular contraction and oxygen consumption. This would imply that the brain possesses some kind of detection mechanisms that would trigger a respiratory response when muscular contraction occurs. Many now agree that both mechanisms are probably present and complementary, or working alongside a mechanism that can detect changes in oxygen and/or carbon dioxide blood saturation.
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Following regeneration in L. variegatus, past posterior segments sometimes become anterior in the new body orientation, consistent with morphallaxis. Following amputation, most annelids are capable of sealing their body via rapid muscular contraction. Constriction of body muscle can lead to infection prevention. In certain species, such as Limnodrilus, autolysis can be seen within hours after amputation in the ectoderm and mesoderm.
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A short-lasting electric field is generated to disturb demersal fish without killing or paralysing them, but rather by causing an involuntary muscular contraction. Electric pulse fishing consumes less energy compared to conventional trawling, due to the lighter trawl, lower fishing speed and lower frictive resistance from the seabed.Quirijns, F.J., Strietman, W.J., Marlen, B. van, Rasenberg, M., 2013. Platvis pulsvisserij, Resultaten onderzoek en kennisleemtes.
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Metabolites are the substances (generally waste products) produced as a result of muscular contraction. They include chloride, potassium, lactic acid, ADP, magnesium (Mg2+), reactive oxygen species, and inorganic phosphate. Accumulation of metabolites can directly or indirectly produce metabolic fatigue within muscle fibers through interference with the release of calcium (Ca2+) from the sarcoplasmic reticulum or reduction of the sensitivity of contractile molecules actin and myosin to calcium.
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This species is found in warm shallow waters, often at the mouths of rivers where it seems to tolerate low salinity levels. It eats small fish and crustaceans. In order to move, water inside the mantle cavity is expelled through the funnel by muscular contraction of the mantle walls. To catch fast moving prey, the contraction is vigorous, sending a jet of water through the funnel which is directed backwards.
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It can also produce movement either by itself or with the help of molecular motors. Actin therefore contributes to processes such as the intracellular transport of vesicles and organelles as well as muscular contraction and cellular migration. It therefore plays an important role in embryogenesis, the healing of wounds, and the invasivity of cancer cells. The evolutionary origin of actin can be traced to prokaryotic cells, which have equivalent proteins.
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Lombard's paradox describes a paradoxical muscular contraction in humans. When rising to stand from a sitting or squatting position, both the hamstrings and quadriceps contract at the same time, despite them being antagonists to each other. The rectus femoris biarticular muscle acting over the hip has a smaller hip moment arm than the hamstrings. However, the rectus femoris moment arm is greater over the knee than the hamstring knee moment.
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Gas exchange and excretion occur through cilia-lined sacs called bursae; each opens between the arm bases on the underside of the disk. Typically ten bursae are found, and each fits between two stomach digestive pouches. Water flows through the bursae by means of cilia or muscular contraction. Oxygen is transported through the body by the hemal system, a series of sinuses and vessels distinct from the water vascular system.
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The progressive symptoms of anatoxin-a exposure are loss of coordination, twitching, convulsions and rapid death by respiratory paralysis. The nerve tissues which communicate with muscles contain a receptor called the nicotinic acetylcholine receptor. Stimulation of these receptors causes a muscular contraction. The anatoxin-a molecule is shaped so it fits this receptor, and in this way it mimics the natural neurotransmitter normally used by the receptor, acetylcholine.
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Movement is performed by small waves of muscular contraction that flow along the body from tail to head. Several waves may occur simultaneously and the worm glides forward slowly and smoothly, the swellings running evenly along the body. It is carnivorous, either sucking the body juices of its prey or swallowing the whole animal. It feeds on protozoans, other small creatures and prey of a size up to its own.
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Inside the chromatophore cell of cephalopods, pigment granules are enclosed in an elastic sac. To change colour, the animal distorts the sac by muscular contraction, changing its translucency, reflectivity or opacity. This differs from the mechanism used in fish, amphibians and reptiles, in that the shape of the sac is being changed rather than a translocation of pigment vesicles within the cell. Some chameleon and anole species are able to voluntarily change their skin colours.
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1st View - The mode of action for this appliance involved many different views throughout the existence of appliance. The initially theory consisted of Haupl-Andersen's ideas who believed that Isometric Muscular Contraction caused by Myotatic reflex activity was the primary way functional adaptation of the appliance took place. The functional adaptation led to a new way of mandibular closing pattern. This view was later supported by Alexandre Petrovic (1984) and McNamara (1973).
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However, water loss during discontinuous gas exchange is only limited during the flutter phase if gas exchange during the flutter phase is convective (or assisted by muscular contraction). From a water conservation perspective, if ventilation during the flutter phase occurs entirely by simple diffusion, there is no benefit to having a flutter phase. This has led to the belief that some other factor may have contributed to the evolution of discontinuous gas exchange in insects.
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Cornu aspersum leaving mucus-conserving trail over dry brick. The belly visibly leaves the ground in two places in a wave motion without dragging. That wave motion is independent of the wave of muscular contraction that drives the locomotion. Snail climbing grass SMC 07 Cornu aspersum leaving mucus-conserving trail, as seen from above The snail secretes thixotropic adhesive mucus that permits locomotion by rhythmic waves of contraction passing forward within its muscular foot.
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Later in life, he suffered from painful hand problems as a result of the radium exposure during this period. Bovie's work was not the first with electricity in surgery. It was known, for example, that electric current above certain frequencies could cut tissue without inducing muscular contraction. Bovie used such knowledge to create his electrosurgical device and he first employed it in neurosurgical cases with Harvey Cushing, known as the father of neurosurgery.
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The meeting took the form of two symposia on Comparative Studies of Muscular Contraction and on the Structure of Ribonucleic Acid, together with sessions for contributed papers. Minutes of the Steering Committee held on 8 December record that there had already been 183 applications to join the Society and 177 to attend the meeting. By the end of 1960, the membership totaled 224. At the King's College meeting W T Astbury and A V Hill were elected Honorary members.
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The strong eccentric contraction prepares the muscles to switch to the concentric contraction in an explosive manner for takeoff. When the athlete drops down to the floor, the body experiences an impact upon landing. The higher the height of the step-off platform, the greater the impact force upon landing. This creates a shock to the body which the body responds to by undergoing a strong involuntary muscular contraction to prevent the body from collapsing on the ground.
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Laryngospasm is an uncontrolled or involuntary muscular contraction (spasm) of the vocal folds. The condition typically lasts less than 60 seconds, but in some cases can last 20–30 minutes and causes a partial blocking of breathing in, while breathing out remains easier. It may be triggered when the vocal cords or the area of the trachea below the vocal folds detects the entry of water, mucus, blood, or other substance. It is characterized by stridor and/or retractions.
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They are activated (i.e.: opened) at depolarized membrane potentials and this is the source of the "voltage-gated" epithet. The concentration of calcium (Ca2+ ions) is normally several thousand times higher outside the cell than inside. Activation of particular VGCCs allows a Ca2+ influx into the cell, which, depending on the cell type, results in activation of calcium-sensitive potassium channels, muscular contraction, excitation of neurons, up-regulation of gene expression, or release of hormones or neurotransmitters.
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In the peripheral nervous system: (1) they transmit outgoing signals from the presynaptic to the postsynaptic cells within the sympathetic and parasympathetic nervous system, and (2) they are the receptors found on skeletal muscle that receive acetylcholine released to signal for muscular contraction. In the immune system, nAChRs regulate inflammatory processes and signal through distinct intracellular pathways. In insects, the cholinergic system is limited to the central nervous system. The nicotinic receptors are considered cholinergic receptors, since they respond to acetylcholine.
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Neostigmine binds to the anionic and ester site of cholinesterase. The drug blocks the active site of acetylcholinesterase so the enzyme can no longer break down the acetylcholine molecules before they reach the postsynaptic membrane receptors. This allows for the threshold to be reached so a new impulse can be triggered in the next neuron. In myasthenia gravis there are too few acetylcholine receptors so with the acetylcholinesterase blocked, acetylcholine can bind to the few receptors and trigger a muscular contraction.
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The Onychophora forcefully squirt glue-like slimesometimes referred to as 'glue', but termed slime in current scientific literature, e.g. , from their oral papillae; they do so either in defense against predators or to capture prey. The openings of the glands that produce the slime are in the papillae, a pair of highly modified limbs on the sides of the head below the antennae. Inside, they have a syringe-like system that, by a geometric amplifier, allows for fast squirt using slow muscular contraction.
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The tooth is hollow and barbed, and is attached to the tip of the radula in the radular sac, inside the snail's throat. When the snail detects a prey animal nearby, it extends a long flexible tube called a proboscis towards the prey. The radula tooth is loaded with venom from the venom bulb and, still attached to the radula, is fired from the proboscis into the prey by a powerful muscular contraction. The venom paralyzes small fish almost instantly.
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Anatomy of the anus and rectum Defecation is the final act of digestion, by which organisms eliminate solid, semisolid, or liquid waste material from the digestive tract via the anus. Humans expel feces with a frequency varying from a few times daily to a few times weekly. Waves of muscular contraction (known as peristalsis) in the walls of the colon move fecal matter through the digestive tract towards the rectum. Undigested food may also be expelled this way, in a process called egestion.
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Here during the attack tonic muscular contraction may occur, leading to increase in muscle tone which may affect the extensor muscles or the flexor muscles symmetrically or asymmetrically. If the patient is standing, the head may be drawn backward and the trunk may arch. This may lead to retropulsion, which may cause eyelids to twitch rapidly, eyes may jerk upwards or the patients head may rock back and forth slowly, as if nodding. The head may tonically draw to one or another side.
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This depolarization voltage spike triggers an action potential which propagates down the postsynaptic membrane leading to muscle contraction. It is important to note that EPPs are not action potentials, but that they trigger action potentials. In a normal muscular contraction, approximately 100-200 acetylcholine vesicles are released causing a depolarization that is 100 times greater in magnitude than a MEPP. This causes the membrane potential to depolarize +40mV (100 x 0.4mV = 40mV) from -100mV to -60mV where it reaches threshold.
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The nerve tissues which communicate with muscles contain a receptor called the nicotinic acetylcholine receptor. Stimulation of these receptors causes a muscular contraction. The anatoxin-a molecule is shaped so it fits this receptor, and in this way it mimics the natural neurotransmitter normally used by the receptor, acetylcholine. Once it has triggered a contraction, anatoxin-a does not allow the neurons to return to their resting state, because it is not degraded by cholinesterase which normally performs this function.
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Nerves control the contraction of muscles by determining the number, sequence, and force of muscular contraction. When a nerve experiences synaptic fatigue it becomes unable to stimulate the muscle that it innervates. Most movements require a force far below what a muscle could potentially generate, and barring pathology, neuromuscular fatigue is seldom an issue. For extremely powerful contractions that are close to the upper limit of a muscle's ability to generate force, neuromuscular fatigue can become a limiting factor in untrained individuals.
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Insects were once believed to exchange gases with the environment continuously by the simple diffusion of gases into the tracheal system. More recently, large variation in insect ventilatory patterns have been documented, suggesting that insect respiration is highly variable. Some small insects do demonstrate continuous respiration and may lack muscular control of the spiracles. Others, however, utilize muscular contraction of the abdomen along with coordinated spiracle contraction and relaxation to generate cyclical gas exchange patterns and to reduce water loss into the atmosphere.
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Glaucine binds to the benzothiazepine site on L-type Ca2+-channels, thereby blocking calcium ion channels in smooth muscle like the human bronchus. Glaucine has no effect on intracellular calcium stores, but rather, does not allow the entry of Ca2+ after intracellular stores have been depleted. Ca2+ influx is a vital component in the process of muscular contraction, and the blocking of this influx therefore reduces the ability of the muscle to contract.Nestler E, Hyman S & Malenka R. Molecular Neuropharmacology: A Foundation for Clinical Neuroscience (2nd ed.).
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When metabolized, fatty acids yield large quantities of ATP. Many cell types can use either glucose or fatty acids for this purpose. Fatty acids (provided either by ingestion or by drawing on triglycerides stored in fatty tissues) are distributed to cells to serve as a fuel for muscular contraction and general metabolism. They are broken down to CO2 and water by the intra-cellular mitochondria, releasing large amounts of energy, captured in the form of ATP through beta oxidation and the citric acid cycle.
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Insects were once believed to exchange gases with the environment continuously by the simple diffusion of gases into the tracheal system. More recently, however, large variation in insect ventilatory patterns has been documented and insect respiration appears to be highly variable. Some small insects do not demonstrate continuous respiratory movements and may lack muscular control of the spiracles. Others, however, utilize muscular contraction of the abdomen along with coordinated spiracle contraction and relaxation to generate cyclical gas exchange patterns and to reduce water loss into the atmosphere.
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These openings may serve to allow the animal to relieve internal pressure by ejecting body fluid (blood) during moments of extreme muscular contraction of the foot. The nervous system is generally similar to that of cephalopods. One pair each of cerebral and pleural ganglia lie close to the oesophagus, and effectively form the animal's brain. A separate set of pedal ganglia lie in the foot, and a pair of visceral ganglia are set further back in the body, and connect to pavilion ganglia via long connectives.
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In the next phase, also termed the expulsive phase, intense pressure is formed in the stomach brought about by enormous shifts in both the diaphragm and the abdomen. These shifts are, in essence, vigorous contractions of these muscles that last for extended periods of time--much longer than a normal period of muscular contraction. The pressure is then suddenly released when the upper esophageal sphincter relaxes resulting in the expulsion of gastric contents. Individuals who do not regularly exercise their abdominal muscles may experience pain in those muscles for a few days.
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Kalckar's breakthrough work was the demonstration that organic compounds, which were phosphorylated during metabolic processes, involved oxygen consumption; oxygen consumption was linked to organic compound phosphorylation. His key experiment demonstrated that in frog muscles where glycolysis had been inhibited with iodoacetate, muscular contraction continued for a short period using phosphocreatine as a source of energy.Kalckar, H. M. Biological phosphorylations: development of concepts. Prentice-hall, Englewood Cliffs N.J, 1969, pp. 171–172 Kalckar referred to this process as “aerobic phosphorylation” (now called oxidative phosphorylation, a biochemical process fundamental to all living organisms).
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A special case of a chemical synapse is the neuromuscular junction, in which the axon of a motor neuron terminates on a muscle fiber. In such cases, the released neurotransmitter is acetylcholine, which binds to the acetylcholine receptor, an integral membrane protein in the membrane (the sarcolemma) of the muscle fiber. However, the acetylcholine does not remain bound; rather, it dissociates and is hydrolyzed by the enzyme, acetylcholinesterase, located in the synapse. This enzyme quickly reduces the stimulus to the muscle, which allows the degree and timing of muscular contraction to be regulated delicately.
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Emotional stress (anxiety, depression, anger) may increase pain by causing autonomic, visceral and skeletal activity and by reduced inhibition via the descending pathways of the limbic system. The interactions of these biological systems have been described as a vicious "anxiety-pain-tension" cycle which is thought to be frequently involved in TMD. Put simply, stress and anxiety cause grinding of teeth and sustained muscular contraction in the face. This produces pain which causes further anxiety which in turn causes prolonged muscular spasm at trigger points, vasoconstriction, ischemia and release of pain mediators.
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Among his students in Bonn were physiologist Nathan Zuntz (1847–1920) and chemist Hugo Paul Friedrich Schulz (1853–1932). Pflüger made contributions in many aspects of physiology, including embryological physiology, respiratory physiology, sensory physiology and electrophysiology. The eponymous "Pflüger's law" (Pflüger's Zuckungsgesetz) is the result of his research on electrical stimulation and its correlation to muscular contraction. In 1868 he founded Archiv für die gesammte Physiologie des Menschen und der Thiere (now Pflügers Archiv: European Journal of Physiology), a publication that became the most influential journal of physiology in Germany.
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Reich expanded on the concept throughout his career. In his 1942 scientific autobiography The Discovery of Orgone, Vol. 1: The Function of the Orgasm, Reich provided the following summary of his findings regarding orgastic potency: it is an outcome of health, he argued, because full orgastic potency can only come about if a person is psychologically free of neurosis (pleasure anxiety absent), physically free from "body armor" (chronic muscular contraction absent), socially free from compulsive morality and duty as imposed by authoritarian and mechanistic ways of life, and has the natural ability to love.: 6-8.
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Actin therefore only became well known in the West in 1945, when their paper was published as a supplement to the Acta Physiologica Scandinavica. Straub continued to work on actin, and in 1950 reported that actin contains bound ATP and that, during polymerization of the protein into microfilaments, the nucleotide is hydrolyzed to ADP and inorganic phosphate (which remain bound to the microfilament). Straub suggested that the transformation of ATP-bound actin to ADP-bound actin played a role in muscular contraction. In fact, this is true only in smooth muscle, and was not supported through experimentation until 2001.
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Regardless of the pathway, as the impulse reaches the atrioventricular septum, the connective tissue of the cardiac skeleton prevents the impulse from spreading into the myocardial cells in the ventricles except at the atrioventricular node. The electrical event, the wave of depolarization, is the trigger for muscular contraction. The wave of depolarization begins in the right atrium, and the impulse spreads across the superior portions of both atria and then down through the contractile cells. The contractile cells then begin contraction from the superior to the inferior portions of the atria, efficiently pumping blood into the ventricles.
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Oxygenated water is taken into the mantle cavity to the gills and through muscular contraction of this cavity, the spent water is expelled through the hyponome, created by a fold in the mantle. The size difference between the posterior and anterior ends of this organ control the speed of the jet the organism can produce. The velocity of the organism can be accurately predicted for a given mass and morphology of animal. Motion of the cephalopods is usually backward as water is forced out anteriorly through the hyponome, but direction can be controlled somewhat by pointing it in different directions.
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The stop-start motion provided by the jets, however, continues to be useful for providing bursts of high speed - not least when capturing prey or avoiding predators. Indeed, it makes cephalopods the fastest marine invertebrates, and they can out accelerate most fish. Oxygenated water is taken into the mantle cavity to the gills and through muscular contraction of this cavity, the spent water is expelled through the hyponome, created by a fold in the mantle. Motion of the cephalopods is usually backward as water is forced out anteriorly through the hyponome, but direction can be controlled somewhat by pointing it in different directions.
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The patient uses an external magnetic programming device to deactivate the electrical stimulation, relaxing the muscular contraction and enabling defecation at a voluntary time. Dynamic graciloplasty may be indicated for patients with a completely destroyed anal sphincter or a torn sphincter with a large gap between both ends that is not amenable to repair. The procedure involves detachment of the gracilis from the leg, preserving both its blood supply and innervation. The muscle is then moved to wrap around the anal canal completely, and also attached to the periosteum of the inferior ramus of the pubic bone.
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In 1962, she concluded her four decades of research in muscle biochemistry with a study of the proteins of smooth muscle in the uterus. Her major work: Machina Carnis: The Biochemistry of Muscular Contraction in its Historical Development which traces all the developments in the field since 1600, was published in 1971 and reissued in paperback in 2009. She was an honorary fellow of Girton College, a co-founder and fellow of Lucy Cavendish College, and an honorary fellow of Caius College, where she was the first (and for a long time the only) woman fellow.
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Electrical stimulation had been utilized as far back as ancient Egypt, when it was believed that placing torpedo fish in a pool of water with a human was therapeutic. FES - which involves stimulating the target organ during a functional movement (e.g., walking, reaching for an item) - was initially referred to as functional electrotherapy by Liberson. It was not until 1967 that the term functional electrical stimulation was coined by Moe and Post, and used in a patent entitled, "Electrical stimulation of muscle deprived of nervous control with a view of providing muscular contraction and producing a functionally useful moment".
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In the dog the ileal orifice is located at the level of the first or second lumbar vertebra, in the ox in the level of the fourth lumbar vertebrae, in the sheep and goat at the level of the caudal point of the costal arch.Nickel, R., Shummer, A., Seiferle, E. (1979) The viscera of the domestic mammals, 2nd edn. Springer-Verlag, New York, USA. By active muscular contraction of the ileum, and closure of the ileal opening as a result of engorgement, the ileum prevents the backflow of ingesta and the equalization of pressure between jejunum and the base of the cecum.
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During physical exertion or moderate intensity exercise lactate released from working muscle and other tissue beds is the primary fuel source for the heart, exiting the muscles through monocarboxylate transport protein (MCT). This evidence is supported by an increased amount of MCT shuttle proteins in the heart and muscle in direct proportion to exertion as measured through muscular contraction. Furthermore, both neurons and astrocytes have been shown to express MCT proteins, suggesting that the lactate shuttle may be involved in brain metabolism. Astrocytes express MCT4, a low affinity transporter for lactate (Km = 35mM), suggesting its function is to export lactate produced by glycolysis.
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Triadin, also known as TRDN, is a human gene associated with the release of calcium ions from the sarcoplasmic reticulum triggering muscular contraction through calcium-induced calcium release. Triadin is a multiprotein family, arising from different processing of the TRDN gene on chromosome 6. It is a transmembrane protein on the sarcoplasmic reticulum due to a well defined hydrophobic section and it forms a quaternary complex with the cardiac ryanodine receptor (RYR2), calsequestrin (CASQ2) and junctin proteins. The luminal (inner compartment of the sarcoplasmic reticulum) section of Triadin has areas of highly charged amino acid residues that act as luminal Ca2+ receptors.
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Vibrational therapy by way of sinusoidal (high-frequency oscillating) electric current was discovered by Kellogg in 1884 to have medical use for increasing blood circulation and passive exercise. In particular, Kellogg invented a vibrating chair used to stimulate vital organs in the lower abdomen. Even today one can visit the Kellogg Discovery Center in Battle Creek, Michigan, and sit on Kellogg's vibrating chair, which is equipped to mechanically oscillate 20 times per second. Furthermore, Kellogg devised an electrotherapy exercise bed in which a sinusoidal current that produced muscular contraction could be delivered without pain for twenty minutes and reportedly achieve the stimulation of a brisk four-mile walk.
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Enzymes are proteins, like the antibodies present in blood or the proteins responsible for muscular contraction. As a consequence, the study of proteins, of their structure and synthesis, became one of the principal objectives of biochemists. The second discipline of biology which developed at the beginning of the 20th century is genetics. After the rediscovery of the laws of Mendel through the studies of Hugo de Vries, Carl Correns and Erich von Tschermak in 1900, this science began to take shape thanks to the adoption by Thomas Hunt Morgan, in 1910, of a model organism for genetic studies, the famous fruit fly (Drosophila melanogaster).
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Adult Lepidoptera have two pairs of membranous wings covered, usually completely, by minute scales. A wing consists of an upper and lower membrane which are connected by minute fibres and strengthened by a system of thickened hollow ribs, popularly but incorrectly referred to as "veins", as they may also contain tracheae, nerve fibres, and blood vessels.. The membranes are covered with minute scales which have jagged ends or hairs and are attached by hooks. The wings are moved by the rapid muscular contraction and expansion of the thorax. The wings arise from the meso- and meta-thoracic segments and are similar in size in the basal groups.
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An avulsion fracture is a bone fracture which occurs when a fragment of bone tears away from the main mass of bone as a result of physical trauma. This can occur at the ligament by the application of forces external to the body (such as a fall or pull) or at the tendon by a muscular contraction that is stronger than the forces holding the bone together. Generally muscular avulsion is prevented by the neurological limitations placed on muscle contractions. Highly trained athletes can overcome this neurological inhibition of strength and produce a much greater force output capable of breaking or avulsing a bone.
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Electrical systole opens voltage-gated sodium, potassium and calcium channels in cells of myocardium tissue. Subsequently, a rise in intracellular calcium triggers the interaction of actin and myosin in the presence of ATP which generates mechanical force in the cells in the form of muscular contraction, or mechanical systole. The contractions generate intra-ventricular pressure, which is increased until it exceeds the external, residual pressures in the adjacent trunks of both the pulmonary artery and the aorta; this stage, in turn, causes the pulmonary and aortic valves to open. Blood is then ejected from the two ventricles, pulsing into both the pulmonic and aortic circulation systems.
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There are a variety of symptoms associated with this condition that are all caused by a loss of myelin, the insulating layer surrounding the neurones. This means the nerve signals are interrupted and slower which will then cause muscle contractions to be fewer and irregular resulting in an increased colon transit time. The faeces being in the colon for a longer time will mean that more water is absorbed leading to harder stools and therefore increasing the symptoms of constipation. This neurological problem can also lead to reduced sensation of rectal filling and weakness of the anal sphincter because of weak muscular contraction so can cause stool leakage.
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With substantial evidence, Hugh Huxley formally proposed the mechanism for sliding filament and is variously called swinging cross-bridge model, cross-bridge theory or cross- bridge model. (He himself preferred the name "swinging crossbridge model", because, as he recalled, "it [the discovery] was, after all, the 1960s".) He published his theory in the 20 June 1969 issue of Science under the title "The Mechanism of Muscular Contraction". According to his theory, filament sliding occurs by cyclic attachment and detachment of myosin on actin filaments. Contraction occurs when the myosin pulls the actin filament towards the centre of the A band, detaches from actin and creates a force (stroke) to bind to the next actin molecule.
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Plyometrics exploit the stretch-shortening cycle of muscles to enhance the myotatic (stretch) reflex. This involves rapidly altering the lengthening and shortening of muscle fibers against resistance. The resistance involved is often a weighted object such as a medicine ball or sandbag, but can also be the body itself as in jumping exercises or the body with a weight vest that allows movement with resistance. Plyometrics is used to develop explosive speed, and focuses on maximal power instead of maximal strength by compressing the force of muscular contraction into as short a period as possible, and may be used to improve the effectiveness of a boxer's punch, or to increase the vertical jumping ability of a basketball player.
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Brownian motors operate specifically to utilise this high level of random noise to achieve directed motion, and as such are only viable on the nanoscale. The concept of Brownian motors is a recent one, having only been coined in 1995 by Peter Hänggi, but the existence of such motors in nature may have existed for a very long time and help to explain crucial cellular processes that require movement at the nanoscale, such as protein synthesis and muscular contraction. If this is the case, Brownian motors may have implications for the foundations of life itself. In more recent times, humans have attempted to apply this knowledge of natural Brownian motors to solve human problems.
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This response can be dramatic; in trained athletes have hearts that have left ventricular mass up to 60% greater than untrained subjects. Rowers, cyclists, and cross-country skiers tend to have the largest hearts, with an average left ventricular wall thickness of 1.3 centimeters, compared to 1.1 centimeters in average adults. Though eccentric hypertrophy is termed 'athlete's heart' it is typically only found in individuals who are aerobically conditioned. For example, weight lifters tend to undergo remodeling which more closely resembles concentric hypertrophy, as the heart does not experience a volume-overload, but instead responds to transient pressure overload as a consequence of increased vascular resistance from pressures exerted on arteries by sustained muscular contraction.
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One using Kinesio Tape only, one stretching only, and one using both Kinesio Tape and stretching. It was found that the usage of Kinesio Tape can increase shoulder ROM, and that stretching had no effect on shoulder ROM if being used alone or when coupled with the Kinesio Tape. A 2014 meta analysis looked at methodological quality of studies, along with overall population effect, and suggested that studies of lower methodological quality are more likely to report beneficial effects of elastic therapeutic taping, thus indicating the perceived effect of using KT is not real. It also suggested that applying elastic therapeutic tape, "to facilitate muscular contraction has no, or only negligible, effects on muscle strength".
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Strength training (resistance training) causes neural and muscular _adaptations_ which increase the capacity of an athlete to exert force through voluntary muscular contraction: After an initial period of neuro-muscular adaptation, the muscle tissue expands by creating sarcomeres (contractile elements) and increasing non-contractile elements like sarcoplasmic fluid. Muscular hypertrophy can be induced by progressive overload (a strategy of progressively increasing resistance or repetitions over successive bouts of exercise in order to maintain a high level of effort). However, the precise mechanisms are not clearly understood; currently accepted hypotheses involve some combination of mechanical tension, metabolic fatigue, and muscular damage. Muscular hypertrophy plays an important role in competitive bodybuilding and strength sports like powerlifting, football and Olympic weightlifting.
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Averages also exist for different types of grip in different positions.Effects of interface factors on the handgrip and pinchgrip force exertion capabilities, muscular contraction speed and endurance Winson W.S. LO, Alan H.S. CHAN, Michael K.H. LEUNG Grip strength increases or decreases depending on the arm position at which the grip strength is being measured. A person's grip strength usually results in having the strongest grip strength when their arm is extended at 90° before their body, as opposed to the other extreme arm positions, rested at one's side or held straight up above one's head. Grip strength is not optimal if one's arm is extended backwards beyond the resting position at the body's sides.
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Originally, the facial feedback hypothesis studied the enhancing or suppressing effect of facial efference on emotion in the context of spontaneous, "real" emotions, using stimuli. This resulted in "the inability of research using spontaneous efference to separate correlation from causality". Laird (1974) used a cover story (measuring muscular facial activity with electrodes) to induce particular facial muscles contraction in his participants without mentioning any emotional state. However, the higher funniness ratings of the cartoons obtained by those participants "tricked" into smiling may have been caused by their recognizing the muscular contraction and its corresponding emotion: the "self-perception mechanism", which Laird (1974) thought was at the root of the facial feedback phenomenon.
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Following this logic, the end of the microfilament that does not have any protruding myosin is called the point of the arrow (- end) and the other end is called the barbed end (+ end). A S1 fragment is composed of the head and neck domains of myosin II. Under physiological conditions, G-actin (the monomer form) is transformed to F-actin (the polymer form) by ATP, where the role of ATP is essential. The helical F-actin filament found in muscles also contains a tropomyosin molecule, which is a 40 nanometre long protein that is wrapped around the F-actin helix. During the resting phase the tropomyosin covers the actin's active sites so that the actin-myosin interaction cannot take place and produce muscular contraction.
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The cardiovascular system responds to changing demands on the body by adjusting cardiac output, blood flow, and blood pressure. Cardiac output is defined as the product of heart rate and stroke volume which represents the volume of blood being pumped by the heart each minute. Cardiac output increases during physical activity due to an increase in both the heart rate and stroke volume. At the beginning of exercise, the cardiovascular adaptations are very rapid: “Within a second after muscular contraction, there is a withdrawal of vagal outflow to the heart, which is followed by an increase in sympathetic stimulation of the heart. This results in an increase in cardiac output to ensure that blood flow to the muscle is matched to the metabolic needs”.
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The helical F-actin filament found in muscles also contains a tropomyosin molecule, a 40-nanometre protein that is wrapped around the F-actin helix. During the resting phase the tropomyosin covers the actin's active sites so that the actin-myosin interaction cannot take place and produce muscular contraction (the interaction gives rise to a movement between the two proteins that, because it is repeated many times, produces a contraction). There are other protein molecules bound to the tropomyosin thread, these include the troponins that have three polymers: troponin I, troponin T, and troponin C. Tropomyosin's regulatory function depends on its interaction with troponin in the presence of Ca2+ ions. Both actin and myosin are involved in muscle contraction and relaxation and they make up 90% of muscle protein.
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Nachmansohn discovered that rapidly contracting muscles contained more phosphocreatine than slowly contracting ones, which eventually led to the hypothesis that phosphocreatine was involved in the regeneration of the ATP that was built up to provide energy during muscular contraction. Leaving Nazi-era Berlin, Nachmansohn arrived in Paris in 1933 and took up a position in the Sorbonne. There he discovered that acetylcholinesterase is present at high concentrations in many different types of excitable nerve and muscle fibres and in brain tissue - lending support for Otto Loewi and Henry Dale's then novel proposal that acetylcholine functions in the transmission of impulses from nerves across junctions to other nerves or to muscles. Nachmansohn obtained very active solutions of acetylcholinesterase from the electric organ of the marbled electric ray (Torpedo marmorata).
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Onuf's nucleus is a distinct group of neurons located in the ventral part (laminae IX) of the anterior horn of the sacral region of the human spinal cord involved in the maintenance of micturition and defecatory continence, as well as muscular contraction during orgasm. It contains motor neurons, and is the origin of the pudendal nerve. The sacral region of the spinal cord is fourth segment (cervical, thoracic, and lumbar being the first three) of vertebrae in the spinal cord which consists of the vertebrae 26-30. This small group of neural cells is located between S1 and S2 or S2 and S3 and although Onuf's nucleus is located primarily in S2, it can extend to the caudal end of the first sacral segment or to the middle part of the third sacral segment.
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Onuf's nucleus is a distinct group of neurons located in the ventral part (laminae IX) of the anterior horn of the sacral region of the human spinal cord involved in the maintenance of micturition and defecatory continence, as well as muscular contraction during orgasm. It contains motor neurons, and is the origin of the pudendal nerve. The sacral region of the spinal cord is the fourth segment (cervical, thoracic, and lumbar being the first three) of vertebrae in the spinal cord which consists of the vertebrae 26-30. While working in New York City in 1899, Bronislaw Onuf-Onufrowicz discovered this group of unique cells and originally identified it as “Group X.” “Group X” was considered distinct by Onufrowicz because the cells were different in size from the surrounding neurons in the anterolateral group, suggesting that they were independent.
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Nerves are responsible for controlling the contraction of muscles, determining the number, sequence and force of muscular contraction. Most movements require a force far below what a muscle could potentially generate, and nervous fatigue is seldom an issue. But, during extremely powerful contractions that are close to the upper limit of a muscle's ability to generate force, nervous fatigue (enervation) -- in which the nerve signal weakens -- can be a limiting factor in untrained individuals. In novice strength trainers, the muscle's ability to generate force is most strongly limited by nerve’s ability to sustain a high-frequency signal. After a period of maximum contraction, the nerve’s signal reduces in frequency and the force generated by the contraction diminishes. There is no sensation of pain or discomfort, the muscle appears to simply ‘stop listening’ and gradually cease to contract, often going backwards.
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In 1870 Eduard Hitzig and Gustav Fritsch demonstrated that electrical stimulation of certain parts of the dog brain resulted in muscular contraction on the opposite side of the body. Translated in: A little later, in 1874, David Ferrier, working in the laboratory of the West Riding Lunatic Asylum at Wakefield (at the invitation of its director, James Crichton-Browne), mapped the motor cortex in the monkey brain using electrical stimulation. He found that the motor cortex contained a rough map of the body with the feet at the top (or dorsal part) of the brain and the face at the bottom (or ventral part) of the brain. He also found that when electrical stimulation was maintained for a longer time, such as for a second, instead of being discharged over a fraction of a second, then some coordinated, seemingly meaningful movements could be caused, instead of only muscle twitches.
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Nerves control the contraction of muscles by determining the number, sequence, and force of muscular contraction. When a nerve experiences synaptic fatigue it becomes unable to stimulate the muscle that it innervates. Most movements require a force far below what a muscle could potentially generate, and barring pathology, neuromuscular fatigue is seldom an issue. For extremely powerful contractions that are close to the upper limit of a muscle's ability to generate force, neuromuscular fatigue can become a limiting factor in untrained individuals. In novice strength trainers, the muscle's ability to generate force is most strongly limited by nerve’s ability to sustain a high- frequency signal. After an extended period of maximum contraction, the nerve’s signal reduces in frequency and the force generated by the contraction diminishes. There is no sensation of pain or discomfort, the muscle appears to simply ‘stop listening’ and gradually cease to move, often lengthening. As there is insufficient stress on the muscles and tendons, there will often be no delayed onset muscle soreness following the workout.
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