The structural organization of muscle fibers makes it possible to produce contractile force
a. What is the fundamental contractile unit of skeletal muscle?
b. What are the names of the bands, lines and zone of the contractile unit of skeletal muscle?
c. Each of the contractile unit region names in (b) contains a letter. What does each of these letters stand for?
d. What changes occur in the contractile unit regions during contraction?
What will be an ideal response?
Answer:
a. The sarcomere is the fundamental contractile unit of the muscle cells.
b. A and I bands, M and Z lines, H zone
c. A–anisotropic (with respect to plane-polarized light), I–isotropic (with respect to plane-polarized light), M–contains myomesin, Z–zwischen (meaning between), H–hell (meaning light)
d. The A band and M line remain unchanged, but the distance between Z lines gets shorter as the I band and H zone get shorter or disappear.
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