Neuroendocrine epithelial cells in the broncho-parabronchial transition of embryonic, immature and mature quail (Coturnix coturnix).

The main objective of this integrated light microscopic, transmission and scanning electron microscopic study was to describe in greater detail the structural pattern and developmental stages of pulmonary neuroendocrine epithelial cells (PNECs) in the broncho-parabronchial transition (BPT) of both developing and mature quail. In mature quail the BPT appeared as a diaphragm opening into the parabronchial vestibulum. Perpendicular sections revealed two bilayered crest-like entrance folds invested by a uniform population of granular cells with lamellar bodies and a brush border of blunt microvilli.

Lamellar inclusions and trilaminar substance in the parabronchial epithelium of the quail (Coturnix coturnix).

The fine structure of the epithelial cells of the parabronchus and their secretory products have been the subject of many studies and have given rise to considerable controversy about their configuration and ultrastructure. The aim of the present study was to investigate the mode of formation and discharge of lamellar bodies of granular cells and the trilaminar substance produced and discharged by the embryologically related squamous atrial and respiratory epithelial cells. The material for light and transmission electron microscopic analysis was collected from 10 mature quail and 3 individuals aged 2 days.

A scanning and transmission electron microscopy study of the parabronchial unit in quail (Coturnix coturnix) and town pigeons (Columba livia).

A combined scanning electron (SEM) and transmission electron microscopy (TEM) investigation was undertaken to gain insight into the complex structural pattern of the atrial compartment and the gas exchange tissue of parabronchial units in quail and town pigeons. The aim was also to depict the changes taking place in the parabronchial unit in the late prehatching and early posthatching periods in quail. The standard SEM and TEM investigation was carried out in 13 mature quail and 8 town pigeons.

The development and differentiation of the parabronchial unit in quail (Coturnix coturnix).

The present study has been inspired by the conflicting data in the relevant literature concerning the embryogenesis of cell types of the parabronchial epithelium and the formation, discharge and distribution of trilaminar substance and lamellar bodies. Lung tissue from embryonic, newly hatched, immature and mature quail was subjected to standard processing for light and transmission electron microscopy. The parabronchial rudiments form shallow primitive atria on embryonic day 13.

An SEM and TEM study of the transition of the bronchus to the parabronchus in quail (Coturnix coturnix).

The main objective was to analyse the transition of the bronchus to the parabronchus in birds and to describe its specific structure in an integrated light microscopic, transmission electron microscopic (TEM) and scanning electron microscopic (SEM) study. Lung tissue from immature and mature quail was subjected to standard processing for paraffin light microscopy, TEM and SEM after intratracheal inflation with fixative. In transverse paraffin and Durcupan semithin sections, the partition incompletely closing the broncho-parabronchial transition has the appearance of a crest-like fold delineating the entrance to the underlying parabronchial vestibulum.