الفهرس 
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Abstract
e -A
The present study was conducted to compare the histology and ultrastructure of the thyroid gland in Rousettus aegyptiacus with different age. This study was conducted on 30 samples of the thyroid gland, 10 for each stage (lactating nonlactating, and adult). In adult animals, the thyriod gland is covered with capsules of fibrous tissues and different size of thyroid follicles filled with colloid stain with H&E. The follicular wall has cubical squamous epithelium. The study showed a highly positive reaction of thyroglobulin with PAS reaction. In non-lactating animals, the follicles are small with reduced colloid stained with H&E and positive reaction with PAS stain. In lactating animals, the follicles are small with reduced colloid stained with H&E and positive reaction with PAS stain. The ultrastructure examination revealed that, the adult thyroid showed large follicles composed of squamous to cubical epithelium with elongated to the round nucleus. with chromatin clumps the follicle filled with large electron-dense homogenous colloid material which has thyroid hormones stored in cavities as glycoprotein. Lactating animals showed small follicles were lined by columnar epithelium with an oval basal nucleus and the follicle was filled with reduced colloid material. Numerous thin finger-like microvillus and colloid droplets appear in the follicle cavity. In
nonlactating animals showing small strong follicles lined by epithelium with an irregular basal nucleus and filled with reduced colloid material.
The adrenal gland -b In the adult Rousettus aegyptiacus, the gland is composed of two parts: cortex and medulla. The cortex has three layers present equally as seen with histological structure. The Ultra-structural observations of the glomerulosa cells have mitochondria with vesicular cristae, a few lipid droplets, and appear as large vacuoles. These droplets are variable in size, mainly round to ovoid with an irregular boundary containing material of electron density and small vesicles of smooth endoplasmic reticulum throughout the cytoplasm. The zona fasciculata is the major portion of the adrenal cortex, with Large that appears in radial cords towards the medulla, it contains a greater number of lipid droplets than those observed in the cells of glomerulosa. There are tubular profiles of smooth endoplasmic reticulum in the form of vesicles that appear a huge number of the cytoplasm than those in the zona glomerulosa. The studies on the non-lactating animals the medulla concentrated laterally take small area than the cortex. The three layers of the cortex are well developed but in lactating animals the medulla is concentrated a centrally taken large area than the cortex and the first layer of the cortex is vacuolated. By using azan stain the cortex reacts positively with azocarmine in both stages. By using periodic acid Schiff the outer layer of zona glomerulosa take a positive reaction. The Ultra-structural observations of the non-lactating animals show that the zona glomerulosa cells have few mitochondria, the nucleus peripheral, a few different size lipid droplets appear as large vacuoles and small vesicles of smooth endoplasmic reticulum appear throughout the cytoplasm. The zona reticular cells appear in the radial cords towards the medulla, they contain a greater number of lipid droplets than those observed in the cells of glomerulosa. In lactating animals, the boundary of the nucleus is not differentiated with many vacuoles scattered in the cortex.