Term
|
Definition
| The plasma membrane of a muscle fiber |
|
|
Term
|
Definition
| The cytoplasm of a muscle fiber |
|
|
Term
|
Definition
An energy-storage polysaccharide abundant in muscle |
|
|
Term
|
Definition
| An oxygen-storing red pigment of muscle |
|
|
Term
|
Definition
| A tunnel-like extension of the sarcolemma extending from one side of the muscle fiber to the other; conveys electrical signals from the cell surface to its interior |
|
|
Term
|
Definition
| The smooth ER of a muscle fiber; a Ca2+ reservoir |
|
|
Term
|
Definition
| The dilated ends of sarcoplasmic reticulum adjacent to a T tubule |
|
|
Term
|
Definition
| A bundle of protein microfilaments (myofilaments) |
|
|
Term
|
Definition
| A threadlike complex of several hundred contractile protein molecules |
|
|
Term
|
Definition
| A myofilament about 11 nm in diameter composed of bundled myosin molecules |
|
|
Term
|
Definition
| A myofilament about 1 nm in diameter composed of a giant protein, titin, that flanks a thick filament and anchors it to a Z disc; stabilizes and centers the thick filament and prevents overstretching |
|
|
Term
|
Definition
| A myofilament about 5 to 6 nm in diameter composed of actic, toponin, and tropomyosin |
|
|
Term
|
Definition
| A protein with a long shaftlike tail and a globular head; constitutes the thick myofilament |
|
|
Term
|
Definition
| A fibrous protein made of a long chain of G actin molecules twisted into a helix; main protein of the thin myofilament |
|
|
Term
|
Definition
| A globular subunit of F actin with an active site for binding a myosin head |
|
|
Term
|
Definition
| Troponin and tropomyosin, proteins that do not directly engage in the sliding filament process of muscle contraction, but regulate myosin-actin binding |
|
|
Term
|
Definition
A regulatory protein that lies in the groove of F actin and, in relaxed muscle, blocks the myosin-binding active sites
|
|
|
Term
|
Definition
| A regulatory protein associated with tropomyosin that acts as a calcium receptor |
|
|
Term
|
Definition
| A springy protein that forms the elastic filaments and anchors the thick filaments to the Z discs |
|
|
Term
|
Definition
| A large protein that links thin filaments to transmembrane proteins, which, in turn, are linked to extracellular proteins; transfers the force of sarcomere contraction to the fibrous connective tissues of a muscle |
|
|
Term
|
Definition
| Alternating light and dark transverse bands across a myofibril |
|
|
Term
|
Definition
| Dark band formed by parallel thick filaments that partly overlap the thin filaments |
|
|
Term
|
Definition
| A lighter region in the middle of an A band that contains thick filaments only; thin filaments do not reach this far into the A band in relaxed muscle |
|
|
Term
|
Definition
| A dark line in the middle of an H band marking the origin of the thick filaments |
|
|
Term
|
Definition
| A light band composed of thin filaments only |
|
|
Term
|
Definition
| A disc of protein to which thin and elastic filaments are anchored at each end of a sarcomere; appears as a narrow dark line in the middle of the I band, and is often called the Z line |
|
|
Term
|
Definition
| A segment from one Z disc to the next; the contractile unit of a muscle fiber |
|
|
