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The sliding filament theory explains the mechanism of muscle contraction based on muscle proteins that slide past each other to generate movement. [1] According to the sliding filament theory, the myosin ( thick filaments ) of muscle fibers slide past the actin ( thin filaments ) during muscle contraction, while the two groups of filaments ...
Depiction of smooth muscle contraction. Muscle contraction is the activation of tension-generating sites within muscle cells. [1] [2] In physiology, muscle contraction does not necessarily mean muscle shortening because muscle tension can be produced without changes in muscle length, such as when holding something heavy in the same position. [1]
The muscle fibers belonging to one motor unit can be spread throughout part, or most of the entire muscle, depending on the number of fibers and size of the muscle. [2] [3] When a motor neuron is activated, all of the muscle fibers innervated by the motor neuron are stimulated and contract. The activation of one motor neuron will result in a ...
Ballistic movements are often powered through elastic energy storage and subsequent recovery mechanisms. The power required to produce the extremely rapid velocities of ballistic movements is made possible through muscle work being stored in elastic elements (such as tendons, aponeuroses, or even muscle).
The endplate potential is thus responsible for setting up an action potential in the muscle fiber which triggers muscle contraction. The transmission from nerve to muscle is so rapid because each quantum of acetylcholine reaches the endplate in millimolar concentrations, high enough to combine with a receptor with a low affinity, which then ...
The action of myosin along the actin filaments causes the shortening and lengthening of the sarcomere; responsible for muscle contraction and relaxation, respectively. Motor proteins are the driving force behind most active transport of proteins and vesicles in the cytoplasm.
Myosins (/ ˈ m aɪ ə s ɪ n,-oʊ-/ [1] [2]) are a family of motor proteins (though most often protein complexes) best known for their roles in muscle contraction and in a wide range of other motility processes in eukaryotes. They are ATP-dependent and responsible for actin-based motility. The first myosin (M2) to be discovered was in 1864 by ...
An impulse from a nerve cell causes calcium release and brings about a single, short muscle contraction called a muscle twitch. If there is a problem at the neuromuscular junction, a very prolonged contraction may occur, such as the muscle contractions that result from tetanus. Also, a loss of function at the junction can produce paralysis. [5]