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Abstract The materials used in the present study were colle cted from Cairo slaughter house. They include 47 embryos and fetuses of different CVR lengths (3.2—120 cm) beside the salivary glands of 24 camels (1—20 years old). The results presented in this investigation elucidate the histological structure and its functional significance of the dromedary camel during ontogenetic stages. The primordium of the parotid salivary gland originated from the bucczal ectodermal epithelium at the mouth fissure at 3.2 Cm CVR length. The mandibular anlage was developed from the epithelium of the oral cavity at the linguogingival groove. The bud of the gland protruded ventrocaudally leaving a fovea at its seat of origin. The bud consisted of elongated mass of irregular shaped cells with spherical centrally located nuclei and light cytoplasm and could be observed in camel fetuses of 3~2 Cm CVR length. The sublingual gland anlage was formed from the linguogingival groove at the root of the tongue as a number of solid ducts. The sublingual primordium was observed at 5.1 Cm CVR -length. —64— By the progressive division of the bud cells of the parotid and the mandibular glands the bud grew and extended as a main solid duct. The cavitation was first started in the old parts of the primordia. The onset of luminization was at the CVR length 6.2 cm in the parotid and 5.1 Cm CVR length in the mandibular gland. The ramification of the primordia started at the CVR length 5.1 Cm in the parotid, ventral buccal and mandibular glands and at 6.2 Cm CVR length in other glands. The solid acini were first observed at the CVR length 13.6 Cm in the parotid, sublingual and buccal glands and at 9.7 Cm in the mandibular. Each acinus consisted of a mass of polygonal or irregul~tr cells with spherical nuclei. The lumZnization of the ramifonn primordia extended into new branches. The walls of the luminized branches were consisted of stratified columnar epithelium of two cell layers. Scattered mucous cells were interposed between the cells of the primordial branches. These cells showed a high reactivity with alcian blue and PAS stains. They were recorded at 23 Cm CVR length in the sublingual -65— and buccal glands while at 21 Cm and 17.5 Cm CVR length among the parotid and the mandibular glands respectively. With the advancement of age, the acini and the prim ordial ducts proliferated. The mucous cells increased and appeared in the cavitated acini at the CVR length 40 Cm however in the mandibular at 21 Cm CVR length. The mucous cells were very few in the paroti& acini. In the mandi bular and sublingual glands the acinus consisted of stratified columnar epithelium of two cell layers with the mucous cells were restricted in the inner one. The cells of the acini of the parotid and ventral buccal glands were well organized in one layer without mucous cells. At late pregnancy most of the acini were well developed. Each acinus consisted of one layer of truncated pyramidal cells with spherical nuclei and a narrow lumen. The parotid and ventital buccal glands were well developed before birth. The development of the end piece of the mandibular and the sublingual glands were similar. The outer layer of the acini gave the demilune while the inner layer gave the mucous acinus. Well developed acini were seen at the CVR length 65.6 Cm and most of then were well developed in the prenatal life of all salivary glands. Small clusters of serous acini were observed inter posed between the lobules of mixed one in the sublingual gland. These acini were detected by the absence of mucous cells. —66— The main ducts of the talivary glands of the camel were represented by the solid ducts produced by the proliferation of the bud cells of each gland at 5.1 Cm Cfl length. After luminization the duct cells arranged as stratified columnar epithelium. By the advancement of age, the epithelium of the main duct of the parotid and the mandibular gland supported by connective tissue propria carrying a number of blood vessels and nerves. Gradually the lumen of the main duct was folded and the goblet cells appeared among its epithel ium. The interlobular ducts were recognizable at the CVR length 21 cm in case of the parotid and the mandibular glands however at 27 cm CVR length in case of the sublingual and buccal glands. They were composed of 2 layers of stratified columnar epithelium with goblet cells. The interlobular ducts of the dorsal and middle buccal glands and sublingual gland were differentiated into small one lined by simple columnar or even cuboidal epithelium and larger one by 2 cell layers of stratified columnar epithelium. The goblet cells were present in the interlobular ducts in the prenatal life. They were few in the sublingual and mandbular glands. However in the 67— postnatal life the goblet cells were observed in the interlobular ducts of the parotid, and ventral buccal, very few in the mandibular and absent in the sublingual, dorsal and middle buccal glands. The striated ducts had never been recognized in the prenatal life of all described salivary glands. The ducts were observed in the prepubertal period and composed of columnar cells with basal striation and surrounded by myoepithelial cells. The striation diminished in senility in the parotid and ventral buccal glands. The camel salivary glands were compound branched tubuloalveolar; they were seromucous. The mesenchy~e (future stroma) of the aforementioned salivary glands showed positive reaction by alcian blue stain particularly at the early stages of pregnancy. The stromal elements, the basement membranes and the free borders of the ducts stained strongly by PAS stain. The goblet cells as Well as the acini were showed PAS—positive reaction in different stages of the prenatal life. So secretory activity started during the period of mid pregnancy. The reaction in the acini and the demilunes was variable in the potnatal life. The acini of the parotid and ventral buccal glands were alcian blue negative. The variation in the alcian blue and PAS staining was due to the different phases of secretion as storage, secretory and exhaustion phases. |