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In skeletal muscles, muscle tension is at its greatest when the muscle is stretched to an intermediate length as described by the length-tension relationship. Unlike skeletal muscle, the contractions of smooth and cardiac muscles are myogenic (meaning that they are initiated by the smooth or heart muscle cells themselves instead of being ...
The Frank-Starling mechanism occurs as the result of the length-tension relationship observed in striated muscle, including for example skeletal muscles, arthropod muscle [4] and cardiac (heart) muscle. [5] [6] [7] As striated muscle is stretched, active tension is created by altering the overlap of thick and thin filaments. The greatest ...
As tension increases in the muscle fibers, the pennation angle also increases. A greater pennation angle results in a smaller force being transmitted to the tendon. [9] Muscle architecture affects the force-velocity relationship. Components of this relationship are fiber length, number of sarcomeres and pennation angle.
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 ...
One feature of the ratio is that there is an optimal gear ratio for each muscle; as the length-tension and force-velocity relationships describe. Length-tension refers to the max tension that can be created over the muscle fiber strain range and force-velocity refers to the power that is possible of the fiber compared to the shortening velocity.
Muscle contraction ends when calcium ions are pumped back into the sarcoplasmic reticulum, allowing the contractile apparatus and, thus, muscle cell to relax. Upon muscle contraction, the A-bands do not change their length (1.85 micrometer in mammalian skeletal muscle), [5] whereas the I-bands and the H-zone shorten. This causes the Z-lines to ...
Similarly, the higher the contraction velocity, the lower the tension in the muscle. This hyperbolic form has been found to fit the empirical constant only during isotonic contractions near resting length. [1] The muscle tension decreases as the shortening velocity increases. This feature has been attributed to two main causes.
When tetanized, the contracting tension in the muscle remains constant in a steady state. This is the maximal possible contraction. [3] During tetanic contractions, muscles can shorten, lengthen or remain constant length. [7] Tetanic contraction is usually normal (such as when holding up a heavy box).