ABSTRACT
The VND consists of several structures which include the vomeronasal duct[VND], the vomeronasal glands[VNGs], vessels and nerves. It is the peripheral organ of the accessory olfactory system which detects some types of pheromones. Several studies are carried on the adult VNO however, no informations are available on the development of the VNGs in cat which represeni one of the examples of early odour perception. This work aim at investigating the development of the cat's VNGs using histological, histochemical, electron microscopic and morphometric techniques. A total number of 24 female cats of different ages was used in this study. The animals were equally divided into Jbur groups [GI, 0-1day, GTh 2 weeks, GIII: 1 month, GIV. 2 months,].After sacrifice, specimens were taken from the VNO for light and electron microscopic studies. with progress of age, the glandular end pieces and ducts gel more branched. Progressive increase in PAS reaction in VNGs with a mild increase in +ve reaction for Alcian blue occurred with development. However, the VND revealed +ve Alcian blue reaction at birth and the reaction increased with age progress. These .tIndings reflect the profuse secretion of neutral mucin and a limited acid mucin. Ultrastructurally the developing VNGs exhibited moderates dense cytoplasm containing basal RER and electeon dense secretory granules which predominant in GI, II. Both electron dense and electron lucent secretory granules get increased with age progress. The lamina propria contained collagen and reticular fibers which increased with age progress. No elastic fibers were present. Fenestrated blood capillaries,non myelinaled and mixed nerve bundles were present also in the surrounding C. T Statistical analysis with ANOVA test revealed a significant increase in count and size of the acini with progress of development. The morphological data in the present study confirm the functional capability of the VNGs at birth. It demonstrates marked postnatal development of the VNGs. The VNGs of the cat are formed of serous, mucous and mixed acini. Acid mucopolysaccharides appear to be produced mainly by the epitheliumn lining of the VND