Mucous blanket of rat bronchus: an ultrastructural study.

The tracheobronchial tree of rats was fixed by fixative vapor "from the front", thus preserving the mucous blanket for morphologic study. Electron microscopic examination of bronchi revealed the existence of osmiophilic myelin-figured lamellae in the lower zone of the mucous blanket. The meaning of this finding is discussed in terms of a 2-layer model of the mucous blanket.