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KIN 3600
Lec 18
Term | Definition |
---|---|
Osteotendinal junction | bone & tendon junction |
Myotendinal Junction | muscle & tendon junction |
Tendons | fusion of all 3 C.T. together @ the 2 distal ends of the muscle forms tendons which becomes continuous with periosteum |
Sarcolemma (plasmalemma) | -Phospholipid bilayer with imbedded proteins -Thickness 7.5 nm -Highly folded |
Sarcosol | Liquid portion of cell/plasma |
Sarcoplasm | Whatever is inside membrane Sarcolemme+sarcosol=sacoplasma |
Myofibrils | -Longitudinal, vertical densely packed individual fibers -Diameter: 1-3mm |
I-band | -Isotropic -Light & uniform |
A-band | -Anisotropic -Dark & dense |
Sarcomere | -Located between two adjacent z-discs -Contractile unit of myofibrils -Series arrangement & parallel arrangement |
Series arrangement | ^ range & velocity of contraction |
parallel arrangement | ^ Force of contraction |
H-zone | Hellerscheibe (German) Middle of A-band |
M-line | -Mittelscheibe -Middle H-zone |
Z disc | Center of each I-band |
Thick filament | -Myosin protein -Organized antiparallel (HEADS ON BOTH SIDES) (Tails twist together ) -Heads contain ATP & Actin -Chemical energy is immediately converted to mechanical energy (Moves myosin head) |
Thin filament | Actin - contractile protein G-actin -Globular protein attach to each other (beads) F-actin - G-actin side by side (necklace) |
Troponin I | binds to actin |
Troponin T | Binds to tropomyosin |
Troponin C | Binds to calcium |
Thick & thin filaments interdigitate in a hexagonal array | 1 Thick: 6 Thin |
Mechanism of muscular contraction | Thin pulled/slides over thick filaments |
What happens to I-band during muscle fiber shortening? | narrows & disappears |
What happens to A-band during muscle fiber shortening? | remains the same length |
What happens to H-zone during muscle fiber shortening? | narrows, disappears, reappears darker color because of over lapping & becomes a wider zone |