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Action Potentials and Muscle Contraction
Mader Human Biology Chapter 12: Muscular System
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Added: March 30, 2008, 8:41 pm
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Muscle Contraction
A muscle contraction (also known as a muscle twitch or simply twitch) occurs when a muscle fiber generates tension through the action of actin and myosin cross-bridge cycling. While under tension, the muscle may lengthen, shorten or remain the same. Though the term 'contraction' implies a shortening or reduction, when used as a scientific term referring to the muscular system contraction refers to the generation of tension by muscle fibers with the help of motor neurons. Locomotion in most higher only through the repeated contraction of many muscles at the correct times. Contraction is controlled by the central nervous system (CNS), which comprises the brain and spinal cord. Voluntary muscle contractions are initiated in the brain, while the spinal cord initiates involuntary reflexes.
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Added: March 30, 2008, 8:38 pm
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