The mechanism of muscle contraction based on actin and myosin filaments.

Hernia- Protrusion of an organ through its body cavity wall.

Myosin heads on thick filaments latch onto myosin-binding sites on actin in the thin filaments, and the sliding begins. The cross bridge attachments form and break several times during a contraction. This generates tension and propels the thin filaments toward the center of the sarcomere. The muscle cell then shortens.

Contains bundled myosin molecules that extend the entire length of the A band. They are connected in the middle of the sarcomere at the M line.

Contains actin molecules and other proteins that extend across the I band and partway into the A band. The Z disc anchors the thin myofilaments.

Consists of hundreds to thousands of muscle cells, connective tissue wrappings, blood vessels, and nerve fibers.

A discrete bundle of muscle cells, segregated from the rest of the muscle by a connective tissue sheath.

An elongated multinucleate cell that has a striated appearance.

Rodlike contractile elements that occupy most of the muscle cell volume.

The contractile unit, composed of myofilaments made up of contractile proteins.

Fibromyalgia- A group of conditions involving chronic inflammation of muscles, their tendons, and connective tissue coverings.

Tetanus- An acute infectious disease caused by anaerobic bacterium and resulting in persistent painful spasms of the skeletal muscles.

Myotonic Dystrophy- Symptons include a gradual reduction in muscle mass and control of the skeletal muscles, abnormal heart rhythm, and diabetes mellitus.

Torticollis- A condition in which the neck stays rotated to one side, keeping the head tilted in that direction.