Ultrastructure of submucosal glands in human anterior middle nasal turbinates

The abundant glands situated in the lamina propria of the human anterior mi ddle nasal turbinate were complex tubules that consist of serous, seromucou s, and mucous cells, either singly or in combination. Serous granules were homogeneously dense, but could have a small lighter core. Seromucous granul es had a dense rim and a large compartment of appreciably lighter density. Gradation between serous and seromucous granules made precise identificatio n of these secretory cell types difficult. Mucous cells were of conventiona l morphology. The secretory tubules, which possessed a complement of myoepi thelial cells, gradually transformed into ducts or the changeover was relat ively sudden. The ductular portions of the tubules consisted either of tall prismatic cells or of shorter columnar cells, both of which lacked secreto ry granules, but had many mitochondria in their supranuclear cytoplasm. In many cases the ducts, for most of their length, consisted of secretory cell s. These glands clearly participate in the elaboration of the glycoconjugat e coat that serves to protect the nasal mucosa and keeps it from drying out .