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Anatomy
Term | Definition |
---|---|
general function of muscles | movement, heat production, posture |
excitability | irritability; muscle cell's ability to be stimulated |
contractility | muscle cell's ability to contract or shorten |
extensibility | ability to extend or stretch |
sarcoplasmic reticulum (SR) | temporarily stores calcium ions (Ca++) |
T tubules | allow electrical signals traveling along the sarcolemma to move deeper into the cell |
triad | T tubule sandwiched between sacs of the SR |
M line | thick (myosin) filaments held together and stabilized by M-protein that form a middle line |
A band | segment that runs the entire length of the thick filaments (anisotropic band) |
I band | segment that includes the Z disk and the ends of the thin filaments where they do not overlap the thick filaments (isotropic band) |
H band | middle region of the thick filaments where they do not overlap the thin filaments |