Friday, 15 October 2010

A usually voluntary muscle made up of elongated, multinucleated, transversely striated muscle fibers, having principally bony attachments. Also called striated muscle.

Skeletal muscles move the body; referred to as ambulation.

There are 4 primary functions of skeletal muscle:
1. Movement
2. Posture or muscle tone

3. Support
4. Heat regulation. Note: There are comments associated with this question. See the discussion page to add to the conversation.
Skeletal muscle is the most abundant tissue in the vertebrate body. These muscles are attached to and bring about the movement of the various bones of the skeleton, hence the name skeletal muscles. The whole muscle, such as the biceps, is enclosed in a sheath of connective tissue, the epimysium. This sheath folds inwards into the substance of the muscle to surround a large number of smaller bundles, the fasciculi. These fasciculi consist of still smaller bundles of elongated, cylindrical muscle cells, the fibres. Each fibre is a syncytium, i.e. a cell that have many nuclei. The nuclei are oval in shaped and are found at the periphery of the cell, just beneath the thin, elastic membrane (sarcolemma). The sarcoplasm also has many alternating light and dark bands, giving the fibre a striped or striated appearance (hence the name striated muscle). With the aid of an electron microscope it can be seen that each muscle fibre is made up of many smaller units, the myofibrils. Each myofibril consists of small protein filaments, known as actin and myosin filaments. The myosin filaments are slightly thicker and make up the dark band (or A-band). The actin filaments make up the light bands (I-bands) which are situated on either side of the dark band. The actin filaments are attached to the Z-line. This arrangement of actin and myosin filaments is known as a sacromere.

Skeletal muscles function in pairs to bring about the co-ordinated movements of the limbs, trunk, jaws, eyeballs, etc.
Skeletal muscles are directly involved in the breathing process

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