MORPHOLOGICAL STUDIES ON THE HUMAN NASAL GLANDS

Abstract

Although histology an, d cytology of the human nasal glands have been studied by many the fundamental knowledge is left inconclusive. The author carried out detailed observations on the glands of human nasal mucosa in 60 cases. The results are summarized as follows 1, There are two kinds of nasal glands, the smaller and larger ones. The former is located in the lamina propria immediately beneath the epithelium, while the latter is found in the deep layer of the mucous membrane. In areas where the mucous membrane is relatively thin., even larger glands' are located beneath the epithelium extending parallel to the epithelial. surface. Thus the position and extension of the glands may depend upon the thickness of the mucous. membrane. 2. The small glands have no excretory ducts but the glandlar tubules (secretory portion) open directly on the epithelial surface. Some of the larger glands have their own excretory ducts, but most of them are lacking of those and open directly in a like manner as do the smaller glands. The excretory duct has a large tubular lumen and is lined with pseudostralified epithelium which is composed of two kinds of cells, the taller and shorter, both of which stand upon the basement membrane and appear like two layered stratified epithelium. The duct is turtuous and its branching was never observed. 3. In parts between the excretory duct and the secretory portion, the striated portions are recognized in some, but the incidence is considerably rare, viz., being found in only 4 cases. The so-called basal striation is found at the basal parts of the epithelial cells of the striated portions, where the cells align in a simple columnar epithelium. A small number of such basally striated cells may appear among the epithelial cells of the excretory duct. Primary branching of the striated portions could be observed. 4. The opening of the nasal gland is observed on the free surface of the epithelium in some cases, and in the epithelial recess in others where two glands may frequently open in a single recess. 5. Neither pure serous nor pure mucous glands present. All of them are mixed glands of either branched tubular or branched tubulo-alveolar form. As the excretory duct does never branch, even the gland with an excretory duct and branched secretory portions may be called the simple gland. In smaller nasal glands the branching of the glandular tubules is rather-simple, whereas the tubules of large glands branch for sevearl times in a complicated manner. Branching of the gland tubules is always observed even in the simplest small glands, and neither unbranched nor intraepithelial gland appear in the human nasal mucosa. 6. About the arrangement of mucous and serous cells in the nasal glands a definite law may be recognized. Namely, the mucous cells are situated at the proximal part near the opening, while the serous cells at the distal part of the gland tubule. The mucous cells form mucous secreting glandular tubules, i.e., the mucous tubules (Schleimrohr), which branch for several times. A rather thick main portion has a dilated lumen which empty into the excretory duct, striated portion or directly on the surface epithelium. To the mucous tubule, mostly tubular or sometimes alveolar serous secreting portion opens. Some of serous glandular tubules primarily branch. Mainly at the terminal portion of branches of the mucous tubule, a plenty of demilunes formed by serous cells are observed. The serous glandular tubules and demilunes form the terminal portion of the nasal glands. Some of the serous glandular tubules open directly on the wall of excretory duct. 7. A number of demilunes are always found in the human nasal glands. The shape and size of demilunes are various, and at the terminal portion of one mucous tubule several numbers of demilunes could be seen. Some of the damilunes project themselves outward and they seem to be the transitional forms into serous glandular tubules.