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 The Master Tissues.—The muscular tissue consists chiefly of rows of cells placed end to end (Fig. 10). These cells have the remarkable property of becoming broader and shorter when stimulated by impulses from nerve cells

, removed from among the fibers of Fig. 13.

n, c, nucleus; p, branches.

The nerve tissue consists of cells with long, spiderlike branches (Fig. 11). Some nerve cells have branches several feet long, so long that they go from the backbone to the foot. The branches are called nerve fibers (Fig. 142). Nerve fibers which carry impulses to the nerve cells are called sensory fibers. The nerve fibers which carry impulses from the nerve cells are called motor fibers. The organs are set to work by impulses through the motor fibers. Besides these two master tissues there are five supporting tissues.

a, b, bundles of white fibers; c, a yellow fiber.

Connective tissue, like all other tissues, contains cells (see Fig. 12), but it consists chiefly of fine fibers. These fibers are of two kinds,—very fine white fibers which are inelastic, and larger yellow fibers which are very elastic (see Fig. 13). Connective tissue is found in every organ, binding together the other tissues and cells. It is interwoven among the muscle cells, and the tendons at the