Answer
In addition to muscle cells(fibers) muscles include nerves, blood vessels and several layers of connective tissue wrappings. From outside in these include the epimysium, the perimysium and the endomysium ( innermost).
Epimysium: this is a sheet of fibrous connective tissue that envelops the whole muscle. On its outer surface the epimysium grades into the muscle fascia, and on its inner surface it projects between muscle bundles or fascicles to form the perimysium.
Perimysium. This is a layer of thick connective tissue that wraps muscle fibers into separate bundles or fascicles. Blood vessels, large nerves, and muscle spindles ( stretch receptors) are in the perimysium.
Work Step by Step
Endomysium is the thin layer of connective tissue that wraps around each muscle fiber. It allows blood vessels , and nerve fibers to reach each muscle fiber so that each myocyte can be stimulated and appropriately nourished. The endomysium also maintains the chemical environment that facilitates the exchange of electrolytes ( sodium, potassium and calcium) between tissue fluid of the endomysium and the nerve and muscle fibers(cells). Excitation of muscle fibers is based primarily on the exchange of Na+ and K+ between interstitial fluid of the endomysium and the neurons and muscle fibers.
