(84)
[Fig. 108]
Fig. 108--*A striated muscle cell* highly magnified, showing striations and
nuclei. Attached to the cell is the termination of a nerve fiber.
Within the sarcolemma are minute fibrils and a semiliquid substance,
called the _sarcoplasm_. At each end the cell tapers to a point from which
the sarcolemma appears to continue as a fine thread, and this, by
attaching itself to the inclosing sheath, holds the cell in place. Most of
the muscle cells receive, at some portion of their length, the termination
of a nerve fiber. This penetrates the sarcolemma and spreads out upon a
kind of disk, having several nuclei, known as the _end plate_.
*The "Muscle-organ."*--We must distinguish between the term "muscle" as
applied to the muscular tissue and the term as applied to a working group
of muscular tissue, which is an organ. In the muscle, or muscle-organ, is
found a definite grouping of muscle fibers such as will enable a large
number of them to act together in the production of the same movement. An
examination of one of the striated muscles shows the individual fibers to
lie parallel in small bundles, each bundle being surrounded by a thin
layer of connective tissue. (See Practical Work.
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