ABSTRACT
The neuroendoerine cells (NE cell) of the lung have been studied in 61 human fetuses by silver stain, immunocytochemical method and electron microscopic technique. The NE cells are mainly located in epithelium of conducting portion with various appearance. Some NE cells are neuron like with several processes. The 5-HT positive NE cells are often found in the epithelium of the primitive alveoli with pyramidal, squamous and tadpole-like appearance. Based upon their ultrastructure, the NE cells are rich in organelles and dense core vesicles (DCV). The NEB is often covered by a layer of cuboidal cells, but no nerve fibers are found among the cells in the NEB.The argyrophil cells usually appear in the 12th week, and reach the maximum number by 20th week. Before the 19th week, the argyrophil cells in the upper segment of the conducting portion are more numerous than those in the lower segment, while after 19th week the condition is just reverse. A regression curve made from the number of argyrophil cells and the thickness of intrapulmonary arteries in different fetal ages shows positive correlation.
