Skeletal or Striated Muscle

The most characteristic features of skeletal muscle are large, multinucleate fibers with cross-striations. Remember that in muscle, fibers are actually multinucleated cells. In the slides of muscle, notice that the perimysium is the loose connective tissue between the fascicles. Iif epimysium is present, observe its dense irregular connective tissue.

Clinical note: Exercise or increased use of specific muscles produce hypertrophy or increased fiber size, while disuse results in muscle atrophy. One form of the hereditary disease muscular dystrophy, in which fibers do not mature properly or survive, results from a defect in the gene for dystrophin, a large protein with poorly understood functions located just inside the sarcolemma.

Examine the striations on longitudinally cut fibers:

• Identify A bands and I bands and
• Be sure you understand what these bands represent in terms of sarcoplasmic organization (Figs. 10-8 through 10-12).

What are the functions of the endomysium and perimysium?

Most skeletal muscle associated with the GI tract is smooth, not skeletal. Why are lingual muscles not composed of smooth muscle?

On to smooth muscle?