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The Development of Parabronchi in the Duck
Author(s) -
Mansour A. A.,
Abdelmohdy F. E.,
Kasab M. A.
Publication year - 2005
Publication title -
anatomia, histologia, embryologia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.34
H-Index - 35
eISSN - 1439-0264
pISSN - 0340-2096
DOI - 10.1111/j.1439-0264.2005.00669_73.x
Subject(s) - hatching , incubation , anatomy , cuboidal cell , atrium (architecture) , basal lamina , biology , incubation period , andrology , epithelium , medicine , zoology , ultrastructure , atrial fibrillation , biochemistry , genetics
This work was carried out on the parabronchi of ducks during the pre‐ and post‐hatching periods. For this purposes, the samples were taken from the embryo of incubated eggs from the 10 th to 28 th day of incubation, at regular interval, and from adult ducks under anaesthesia. The parabronchi first appeared at 14 th day of incubation as out‐pouches, from the secondary bronchi, with solid free end invading the surrounding mesenchym. These pouches was lined by high cuboidal cells rested on PAS positive basal lamina, the cells showed free luminal quarter, which indicated an apocrine secretion. At 17 th to 22 nd day of incubation, irregularities invading the underlying tissue were observed. This invading part was club‐shape forming the future atrium and air capillaries. At 24 th to 28 th day of incubation the parabronchi were observed at the center of a polygonal shape lobule (lung lobule), it was lined with squamous cells at the head of the clubs, while atrium was lined with cuboidal cells at both side of the stalk (interatrial septum), and the air capillaries was lined with attenuated squamous cells. Because of the breathing of the duck started before hatching the structure of the parabronchi was similar in post‐hatching period to that of late stage of pre‐hatching period. The wall of parabronchi was pierced by a number of openings leading to the atrium. The lining epithelium was followed by a layer of smooth muscles, which formed a sphincter around the opening of the atrium regulating the amount of air passed to the atrium and air capillaries to avoid hyperventilation. The E.M. picture revealed that, the epithelium of parabronchi was squamous and displayed a scarce number of microvilli, while that of the atrium was cuboidal with a large number of microvilli, the cells of both contained osmiophilic multilamiller bodies that extruded to the surface. Under the epithelium of parabronchi, there were: smooth muscle cells, macrophages, mast cells, collagen fibers, and fibroblasts, while in the interatrial septum between the epithelium on both side there were collagen fibers and fibroblasts only.