. Cunningham's Text-book of anatomy. Anatomy. SPECIAL END ORGANS. 863 ENDINGS OF NERVES OF GENERAL SENSATIONS. The peripheral endings of the nerves associated with the special senses have been described in the preceding pages. Under this heading will be considered the terminations of those sensory nerves which are widely distributed throughout the body and are associated with the muscular sense and the senses of pressure, heat, cold, and pain. These nerves may end as fine ramifications of the axis cylinders lying free amongst the tissues, or in special end organs where the terminations of the
. Cunningham's Text-book of anatomy. Anatomy. SPECIAL END ORGANS. 863 ENDINGS OF NERVES OF GENERAL SENSATIONS. The peripheral endings of the nerves associated with the special senses have been described in the preceding pages. Under this heading will be considered the terminations of those sensory nerves which are widely distributed throughout the body and are associated with the muscular sense and the senses of pressure, heat, cold, and pain. These nerves may end as fine ramifications of the axis cylinders lying free amongst the tissues, or in special end organs where the terminations of the axis cylinders are surrounded by connective tissue FREE NERVE-ENDINGS. Free nerve-endings are found chiefly in the epithelium covering the skin or the mucous membranes. The nerve-fibres, after subdividing in the sub-epithelial connective tissue, lose success- ively their medullary and primi- tive sheaths and are continued as naked axis cylinders, which, if stained with gold chloride, are seen to consist of fine varicose filaments. The axis cylinders subdivide and form primary and secondary plexuses, and from the latter numerous fibrillse pierce the sub-epithelial base- ment membrane and ramify be- tween the overlying epithelial cells where they end in minute knobs of flattened discs. In the epidermis the nerve fibrillse are limited to the stratum mucosum, but in the cornea they reach the surface layers of epithelium (Fig. 739). Free nerve-endings also occur around the sudoriferous glands, in the papillae and root sheaths of the hair follicles, in the sub-epithelial and intermuscular connective tissues, and in serous membranes. :. j J Modifications of free nerve-endings J are seen in the tactile discs or cells of |tj Merhel; here the neuro-fibrillse end in the deeper layers of the epidermis in crescentic or cup-shaped expansions, in contact with large, modified epithelial cells. These tactile discs are well marked in the pig's snout (Fig. 740). SPECIAL END ORGANS. Fig
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1914
