الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
This study was carried out on 50 healthy mature silver carp fishes to describe the structure of the skin on the head region using light, scanning and transmission electron microscopy. The skin of head region in the silver carp fish was composed of epidermis of, dermis and hypodermis.
The epidermis of the upper lip was of highest thickness and was characterized by the presence of numerous club cells, eosinophilic granular cells, rodlet cells and large number of metachromatic mucous goblet cells, which showed positive reaction with PAS. The sensory organs were organized into ampullay organ and tuberous organ. The dermal layer was composed of collagen fibers, nerve fibers and blood vessels as well as many telocytes.
The epidermis of the lower lip was thicker and was consisted of eosinophilic club cells. In the nostril region, the epidermis was composed of eosinophilic club cells, eosinophilic granular cells, small number of mucous goblet cells, which exhibited a metachromatic reaction. Between basal cells, small lymphatic spaces were present and contained small lymphocytes and some rodlet cells. The dermis contained nerve trunk. Telocytes density was highest in the dermis of lips
The epidermis of the operculum was characterized by presence of eosinophilic club cells and the tuberous organ. In the eye region, eosinophilic granular cells, club cells as well as large numbers of mucous goblet cells were found. Both club cells and mucous cells showed weak positive reaction with PAS. Pear-shaped taste buds were also observed. The sense organs were organized into tuberous and ampullay organs. Telocytes density was lowest in the dermis of the eye.
In the snout region, the epidermis contained eosinophilic club cells and mucous goblet cells. Eosinophilic granular cells were observed in the epidermis and showed PAS-positive reaction. In the dermal layer, single smooth muscle fibers layer were randomly scattered followed by skeletal muscle. Special type of blood vessel could be observed in the hypodermis.
As shown by scanning electron microscopy, the surface view of the skin of the lower lip revealed that it was covered by polyhedral shaped epidermal cells, which showed a fingerprint-like pattern. Many openings for canal neuromasts and mucous cells could be found. The surface of the skin of upper lip was characterized by the presence of taste buds and openings of lateral line system, while the skin of the eye region showed tuberous receptor organ. Superficial neuromasts were noticed and showed a characteristic ring-like pattern. Lateral line system and their associated pores were appeared at the surface of the skin of nostrils. A Superficial neuromast was also observed. Openings of mucous cells and mucus blobs were largely distributed between the epithelial cells.
As observed by transmission electron microscopy, the cytoplasm of the epidermal layers appeared electron-dense except for the superficial layer, where the cytoplasm were electron lucent and contained many vacuoles and few profiles of rER. The epidermis contained mucous cells, rodlet cells and stem cells. The cytoplasm of club cells is rather poor in organelles. The plasma membrane shows invaginations throughout its length. Neutrophils and eosinophilic granular cells were also demonstrated as important immune cells in the epidermis of the upper lip. Lymphocytes and basophils were seen with macrophage in the epidermal layer of the upper lip. Numerous telocytes were demonstrated between the collagen fibers of the dermis and bundles of myelinated nerve fibers.