Main Subjects : Small Animal Histology


Anatomical and histological structure of the cornea in Sparrow hawk Accipiter nisus

Hamid H. Hamid; Ameer M. Taha

Iraqi Journal of Veterinary Sciences, 2021, Volume 35, Issue 3, Pages 437-442
DOI: 10.33899/ijvs.2020.126976.1424

The current study conducted to investigate the anatomical and histological structure of the cornea in sparrow hawk accipiter nisus. By using an optical microscope and histological stains. Anatomical results showed that the cornea composed of two parts, the peripheral cornea and the central cornea, and there was variation in corneal thickness according to the anatomical region. Histologically, the cornea consists of five layers. The first layer of the central cornea consists of non- keratinized stratified squamous epithelial tissue composed of four rows of cells. Whereas, Bowman's membrane appeared clear and thicker on the dorsal side than on the ventral side. The corneal stroma consists of collagen fibers arranged in three secondary layers within the stroma. The corneal stroma also distinguished by the presence of fibroblast cells, which randomly distributed among the collagen fibers. The Descemet membrane appeared clear and equal in thickness between the dorsal and ventral sides. The endothelium tissue appears in the form simple squamous epithelia. The histological structure of the cornea root seemed similar to its formation in the central cornea. Still, it characterized by the presence of pigment cells spread in the stromal corneal root. Among the distinct results that appeared in this study is the presence of blood vessels spreading in the root of the cornea. The study concluded that the anatomical and histological structure of the cornea in this bird distinguished by some specialties that contribute to increasing the effectiveness of the function of the cornea in this bird.

Comparative histological and histochemical study of the ileum in two different birds

Ameer M. Taha

Iraqi Journal of Veterinary Sciences, 2021, Volume 35, Issue 3, Pages 479-487
DOI: 10.33899/ijvs.2020.127046.1447

This study aimed to know the comparative histological structure and histochemistry of the Ileum in two birds that are the Turkey (Meleagris gallopavo) and the Cockatiel (Nymphicus hollandicus) using histological stains and histochemical techniques. The results showed that the Ileum wall in the two birds is composed of the histological layers that make up the rest of the gut wall, with many differences between them. The villi appeared in Turkey in various shapes, longer and more numerous than in the Cockatiel. The villi lined with a simple epithelial tissue in the two birds, containing the goblet cells. Lieberkuhkn''s crypts under the villi appeared in the two birds and had spherical secretory, and some secretory units contained the enteroendocrine cells. The Muscularis Externa appeared distinctively in Turkey than in the Cockatiel, and it was of three sublayers while in the Cockatiel from two sublayers. Histochemical results showed medium to a strong positive response to the epithelial tissue to AB pH 1, AB pH 2.5, PAS techniques while a weak positive in the intestinal glands to these techniques, with varying degrees between the two birds. While the response was positive for BP technique in the epithelial tissue and negative in the glands, as well as the same response appeared for the SB technique. The current study concluded that the Ileum structure in the two birds is identical with histological and histochemical differences that are appropriate to the nature of each bird''s food.

Development of the wing bones in quail’s embryo; Coturnix japonica

Hadia K. Zorab; Kamal A. Salih

Iraqi Journal of Veterinary Sciences, 2021, Volume 35, Issue 1, Pages 129-137
DOI: 10.33899/ijvs.2020.126438.1324

Quail is an essential model in avian research because of economic importance in poultry industries around the world. Furthermore, its use in the experimental embryology research field. Therefore, this study aimed to identify the onset of chondrification and ossification of the wing bones also to summarize the main histological sequences related to the formation of the humerus in Japanese quail. Six embryos were taken every 24 hrs from 3-16 days of incubation. Three embryos were prepared and stained with Alcian blue and Alizarin red for cartilage and bone, respectively. The other three embryos have been processed for histological examination. The Macroscopical findings showed that the humerus, radius, ulna, coracoid, scapula, third, and fourth metacarpals were chondrified on 5th day. However, first signs of ossification were observed in the humerus, radius, and ulna on 8th day. While the minor digit remained none ossified at prehatching. The microscopical stages of developing humerus associated with the limb bud, apical ectodermal ridge formation, and chondrocyte differentiation on 3rd, 4th, and 5th day, respectively. The cartilage template of the humerus was established on 6th day. The diaphysis and epiphyses of the humerus were formed on 7th and 8th day, correspondingly. The periosteal-bone collar was formed on 8th day, and vascularization of chondroepiphysis has occurred on 9th day. There was a difference in the timing of chondrification and ossification in the forelimb skeleton and humerus developed by the endochondral mechanism. The obtained results should be considered in teratological and molecular studies in skeletogenesis.