Research microscopic morphology of lung in small ruminants

Abstract

Goat lungs contain within their structure intrapulmonary airways consisting of intrapulmonary bronchi, bronchioles and terminal bronchioles composed of pulmonary lobules, respiratory alveolar ducts and alveoli of the lungs. In the pulmonary stroma the parenchymal gap is made up of loose connective tissue and outside the pulmonary alveoli. Extra-lobular bronchi within pulmonary stroma have the following histological structure: mucosa, lamina propria, muscular mucosal tunic and the fibrocartilagenous adventitia. The terminal bronchioles wall is formed by an epithelium that is simple cubic and Clara cell secretory granules that present the apical pole. Lamina propria is composed of smooth muscle and elastic fibers that gradually decrease and adventitia is reduced to extinction. Intralobular bronchioles or bronchi are located in the respiratory parenchyma lumen presents a characteristic festooned with pleats or folds mucosa showing longitudinal ciliated columnar epithelium simple with few goblet cells. In the respiratory bronchioles we find simple cubic epithelium and the alveolar epithelium is the ducts flattens. Alveoli presents a very thin wall papered by simple squamous epithelium. Noted that the interalveolar septum consists of two layers of squamous cells separated by thin elastic fibers, fiber cross-linking, typically the capillaries, connective matrix and cells of alveolar septal cells or macrophages. Alveolar macrophages are located between alveolar epithelial cells or inside the alveoli and presents an oval-shaped nucleus placed excentric. Alveolar epithelium shows cells arranged in a single row and consists of: First order pneumocytes or membranous pneumocytes, order II pneumocytes or pneumocytes granulosa with a brushed edge and alveolar macrophages. In the First-order alveolar cells they appear extremely flattened, with a heterochromatic nucleus that protrufes in the lumen and covers the alveoli. The second order alveolar cells appear interspersed among the first-order alveolar cells and appear clustered in interavleolar septa.They cubical spheroid core is centrally located and acidophile cytoplasm.