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Chapter 7
The Muscular System 7.1-7.3
Term | Definition |
---|---|
Skeletal Muscles | Muscles that are cylindrical, have many nuclei, alternating light and dark bands. The muscles attach directly to the skeleton or skin. Voluntarily controlled. |
Cardiac Muscle | Muscles of the heart. Striated and cylindrical with one to two nuclei. These muscles are branched and have intercalated disks. Involuntarily controlled. |
Smooth Muscle | Located within body organs. Spindle shaped cells that are narrow and have one nucleus. Involuntarily controlled. |
Endomysium | A layer of loose connective tissue that surrounds each muscle fiber. |
Fascicle | A group of muscle fibers bundled together. |
Perimysium | The connective covering surrounding fascicles. |
Epimysium | The outermost connective tissue layer that surrounds the entire muscle. |
Tendon | An accumulation of collagen fibers that attach a muscle to a bone. |
Sarcolemma | The plasma membrane of a muscle fiber. |
Sarcoplasm | The cytoplasm of a muscle fiber. |
Sarcoplasmic reticulum | The endoplasmic reticulum of a muscle fiber. |
T Tubules | Conduct impulses for a muscle cell that reach from the sarcolemma to the sarcoplasmic reticulum. |
Myofibrils | Bundles of myofiliaments. Myofibrils are the part of the muscle that contract. |
Myoglobin | A protein and pigment that acts as oxygen storage molecule. |
Sarcomeres | Repeating units found found within a muscle, made up of Z lines, A bands, H zones, and I bands. |
Z Lines | Two dark vertical lines that mark the ends of a sarcomere. |
I Band | A region of thin filaments at the ends of a sarcomere that attach to the Z Line. |
A Bands | Regions of thick and thin filaments |
H Zone | A region in the center of A bands that only contain myosin. |
Thick Filaments | A filament made up of only myosin and is part of the A Band and H Zone. |
Thin Filaments | Made up of three proteins: Actin, tropomyosin, and troponin. |