skeletal muscle

a muscle that provides the force to move a part of the skeleton. Skeletal muscles are attached to the bones by tendons and usually span a joint, so that one end of the muscle is attached via a tendon to one bone and the other end is attached to another bone. Skeletal muscles work in reciprocal pairs (see antagonistic muscles) so that a bone can be moved in opposite directions. Skeletal muscle is composed of numerous slender, tapering muscle fibers, each of which is bounded by a membrane (sarcolemma) and contains cytoplasm (sarcoplasm). Within the sarcoplasm are the longitudinal contractile fibrils (myofibrils), organized into arrays (sarcomeres) that give a striped appearance when viewed microscopically. Contraction of skeletal muscle is typically under voluntary control of the central nervous system. Each muscle fiber is stimulated to contract by nerve impulses conducted along a motor neuron and transmitted to the fiber via a neuromuscular junction. A single neuron may activate from several up to hundreds of muscle fibers. Also called striated muscle; voluntary muscle. Compare cardiac muscle; smooth muscle.

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Psychology term of the day

October 18th 2024

social representation

a system, model, or code for unambiguously naming and organizing values, ideas, and conduct, which enables communication and social exchange (i.e., at the levels of language and behavior) among members of a particular group or community. [term coined and theory elaborated by Romanian-born French psychologist Serge Moscovici (1925– )]