Abstract
A study was made of the distribution of sensory nerve-endings in the human gum. Sections were cut at 30μ on a freezing microtome and impregnated by SUZUKI's silver-method. The results obtained are as follow:
1. The epithelium of the human gum is of stratified squamous nature and can be divided into the inner and outer border-part. The development of papillae in the outer border epithelium is better than that in the inner border epithelium. The density of the nerve supply in lamina propria of the human gum seems to coordinate with the development of papillae in the locality as in the case of rabbit's palate and tongue.
2. In lamina propria of the human gum there occur many non-capsulated corpuscles. They exhibit a great variety in type. But, the most common form of them belongs to a simple or complex glomerular type. They are mainly composed of a few thick myelinated fibers accompanied with thin fibers derived from an unmyelinated nerve. Beside above mentioned end-organs, the lamellar corpuscle, the capsulated sensory corpuscles resembling KRAUSE's and MEISSNER's are rarely found in lamina propria.
3. In the basal part of the interpapillar cristae of the epithelium there occurs a few aggregation of so-called MERKEL's tactile cells that belong to the first type of tactile cell after IMAKO-SUZUKI, in which a nerve fiber terminates in its cytoplasma under the flat or elliptical nucleus forming a disc-like termination with a vacuole. They are generally found in the lingual side of the human gum.
4. In the human gum, as in other mammals, there occur two sorts of the intraepithelial nerve-fibers forming a simple type of free endings: one is a thick fiber originated from a myelinated nerve and the others are branches of an unmyelinated one. Of these thick nerve-fibers in the latter case, some are branches from the end-organs situated in the same papilla. The thin nerve-fibers tend to be adjacent to the thick fibers only in the latter cases, but in the interpapillar cristae they penetrate independently into the epithelium.
5. The presence of so many nerve-endings, such as glomerular non-capsulated, KRAUSE's, and MEISSNER's corpuscla in lamina propria suggests that human gum has high sensibility.
