Which of the following best describes muscle B compared with muscle A?
Adapted for rapid contraction
Composed of larger muscle fibers
Fewer mitochondria
Innervated by smaller nerve fibers
Muscle B is characteristic of a slow-twitch muscle (type 1) composed of predominantly slow-twitch muscle fibers. These fibers are smaller in size and are innervated by smaller nerve fibers. They typically have a more extensive blood supply, a greater number of mitochondria, and large amounts of myoglobin, all of which suppo high levels of oxidative phosphorylation.
Muscle