Ultrastructure of the mucociliary interface in the nasal mucosa of the chicken.

The ultrastructure of the extracellular mucous blanket at the nasal cavities of the chicken was preserved by a method that stabilizes primarily carbohydrate moieties. The cilia were apparently fixed as if "frozen" in the act of beating. The blanket was markedly heterogeneous, with a basic fibrous structure, and it contained membrane remnants. The lumenal surface of the blanket was smooth, but the surface in contact with the cilia penetrated to varying depths between the ciliary shafts. The findings are discussed in terms of the assumptions made by others on the basis of indirect evidence.