Light and electron microscopic characteristics of the various lung endocrine cell types.

Morphological and histochemical studies on APUD-cells in the lung epithelium are reviewed. Common features of these cells are their capacity to produce and store amine, their argyrophilia and their characteristic cytoplasmic secretory granules. Based on the fine structural morphology of the secretory granules three types of cells were observed in human foetal lung. In the human adult lung, endocri…