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Skeletal Muscle Fiber Location and Composition
Nerve Supply to Muscle Fibers
Muscle Contraction Physiology
are located inside muscles, where they are organized into bundles called […]
From the Z discs, the thin filaments extend inward toward the […]
Each skeletal muscle fiber is stimulated to contract by chemicals released […]
As a motor neuron approaches the surface of a muscle fiber, the myelin sheath ceases and the axon splits into a small cluster of fine terminal branches.
As the action potentials travel down the T tubules, calcium channels in the nearby terminal cisternae of SR open, and Ca2+ ions diffuse into the surrounding sarcoplasm. The Ca2+ ions bind to troponin proteins embedded along the thin filaments and the contraction process begins.
In skeletal muscle fibers, electrochemical activity triggers myofilament movement. These linked events are referred to as excitation-contraction coupling.
ACh receptors are embedded in the sarcolemma at the neuromuscular junction. This is the neurotransmitter that is released by the terminal branches of a motor neuron.