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Tetanic contraction can exist in a variety of states, including isotonic and isometric forms—for example, lifting a heavy box off the floor is isotonic, but holding it at the elevated position is isometric. Isotonic contractions place muscles in a constant tension but the muscle length changes, while isometric contractions hold a constant ...
The rate at which the nerve impulses arrive is known as the motor unit firing rate and may vary from frequencies low enough to produce a series of single twitch contractions to frequencies high enough to produce a fused tetanic contraction. Generally, this allows a 2 to 4-fold change in force.
Tetany or tetanic seizure is a medical sign consisting of the involuntary contraction of muscles, which may be caused by disorders that increase the action potential frequency of muscle cells or of the nerves that innervate them.
This is a popular state equation applicable to skeletal muscle that has been stimulated to show Tetanic contraction. It relates tension to velocity with regard to the internal thermodynamics. The equation is (+) (+) = (+), where is the tension (or load) in the muscle
Local tetanus is an uncommon form of the disease, in which people have persistent contraction of muscles in the same anatomic area as the injury. The contractions may persist for many weeks before gradually subsiding. Local tetanus is generally milder; only about 1% of cases are fatal, but it may precede the onset of generalized tetanus. [1]
The rate of muscle twitch contractions and relaxations are thermally dependent (Q 10 of 2.0-2.5), whereas maximum contraction, e.g., tetanic contraction, is thermally independent. [ 6 ] Muscles of some ectothermic species. e.g., sharks, show less thermal dependence at lower temperatures than endothermic species [ 4 ] [ 7 ]
The tetanic fade is the failure of muscles to maintain a fused tetany at sufficiently high frequencies of electrical stimulation. Non-depolarizing blockers have this effect on patients, probably by an effect on presynaptic receptors. [16] Depolarizing blockers do not cause the tetanic fade.
[28] [29] In 1909, with Carl Voegtlin he finally established the direct importance of calcium in tetany, and thereby muscle contraction. [30] [31] [32] From 1909 MacCallum investigated a unique tetanic condition called gastric tetany, in which parathyroid glands are normal.