The pattern of ciliation and the development of the epithelial lining of the respiratory tract in the neonatal kid: a scanning electron microscopic study

The pattern of ciliation and the development of the epithelial lining of the respiratory tract was investigated in 20 Cashmere kids, aged between 6 h to 21 days. Samples were taken from the alar and basal folds, nasal conchae, nasal septum, nasopharynx, epiglottis, vocal fold, infraglottic cavity, trachea, extrapulmonary bronchus, and parenchyma to include respiratory bronchi and alveoli. The samples were routinely prepared and evaluated with scanning electron microscopy and light microscopy. The results showed that cilia were more densely packed and more extensively distributed within the rostral region of the nasal cavity of the kids. Large patches of non-ciliated microvillous cells usually seen in adult goats were not a feature of the kid. It was also noted that the epithelium covering the nasal septum was heavily ciliated in newborn to 3-day-old kids. From that age onwards, the epithelium became deciliated to attain a ‘moth eaten’ appearance. Bronchioles in kids were poorly developed, with respiratory bronchioles being rarely encountered in the first week of life. A cell type characterized by a wrinkled, large apical surface presenting short, apical microvilli, was frequently observed in the larynx and trachea of the kid. Lung parenchyma frequently presented evidence of alveoli formation, whereas alveolar pores were less numerous.