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

February 11th 2025

clerical aptitude

1. the ability to learn specific skills required for office work, such as perceptual speed (e.g., comparing names or numbers), speed in typing, error location, and vocabulary.

2. the measure of individual abilities in the following areas: vocabulary (understanding words and ideas), arithmetic (handling figures easily and accurately), and checking (recognizing similarities and differences rapidly).