unit 10 review Essay
Check Your Recall
Label the following terms on Figure 10.13.
10.13 Basic skeletal muscle structure
10 S 7
Label the following terms on Figure 10.14.
Ⅺ A band
Ⅺ I band
Ⅺ Sarcoplasmic reticulum
Ⅺ Z disk
10.14 Skeletal muscle fiber
The striations in skeletal muscle fibers are attributable to
a. light and dark pigments found in the …show more content…
________________________________________ The cells lack striations and sarcomeres.
Skeletal, some cardiac
________________________________________ The cells are multinucleate.
10 S 9
Check Your Understanding
Critical Thinking and Application Questions
Would a muscle cell be able to produce a functional contraction if it lacked T-tubules? Explain.
Without T-tubules, the action potential propagated along the sarcolemma would not have access to the inside of the muscle fiber or to the terminal cisternae. For this reason, a skeletal muscle fiber without T-tubules would not release adequate numbers of calcium ions to initiate a contraction.
The drug Botox® is made from the toxin of the bacterium Clostridium botulinum. It is injected subdermally to minimize fine lines and creases in the face. The toxin prevents motor neurons from releasing acetylcholine. How would this produce the desired cosmetic results? What could happen if this toxin were absorbed systemically?
The toxin prevents the muscles in the forehead from contracting, which reduces the appearance of wrinkles.
If absorbed systematically, the toxin could cause paralysis of all muscles, including the respiratory muscles.
Myasthenia gravis is an autoimmune disease in which the immune system produces antibodies that attack the