Hrvoje Lucić: Histological and histochemical characteristics of some organs of the striped dolphin (Stenella coeruleoalba) from the Adriatic Sea. Master of Science Thesis. Faculty of Veterinary Medicine University of Zagreb. Zagreb. 2002.

Abstract

Histological and histochemical characteristics of the striped dolphin were investigated and compared with the other sea mammals, especially whales, and with the land mammals, especially man and domestic mammals. The bottlenosed dolphin as a resident species in the Adriatic Sea was included in this work as well, and as same morphological researches on bottlenosed dolphin was done before. We had the possibility to compare it with the striped dolphin.

Lymph nodes of investigated animals are different compared to most of the domestic animals. Lymph folicles are in cortex same as in medulla and they are not cleary separated. Thymus have not the lymph folicles which was described in some marine mammals, and in thymus medulla are more small llassall corpuscles.

Special characteristic of the airway mucosa is higher amount of the elastic fibers. Elastic fibers were grouped in submucosal layer and layer near to the cartilage of the smalest airways. Openings of the tenninal bronchs to the alveolar sacs have a well developed sphincter muscles which are higly positive on the oxidative enzimes. That muscles were present on the bronchiolar branching too, and can close its lumen completely. Dubble capilaries supply the interalveolar wall of the blood-air barierre.

The PAS-positive juxtaglomerular cells were present in the afferent arteriole of the renal corpuscle. The cells of the proximal tubules and cells of the distal tubules have a very high level of metabolic activity which was shown by positive reaction of the oxydative enzimes. The adrenal cortex of the striped dolphin is not so lobulated as in bottlenosed dolphin, and cells of the zona glomerulosa were arranged in the longitudinal layers. According that, cell arrangement of the adrenal cortex of the striped dolphin was similar to those of man, while cell arrangement in bottlenosed dolphin were more like to those of cow-. One regressive corpus luteum on the ovarium surface was visible in the female striped dolphin. Each of the mammary glands terminate with one sinus, one papillary chanel, papillary orifice and one papilla. Gland is lobulated with strong trabeculaes of connective tissue.

Germinative epithelium of the seminiferous tubules consist of more cells layers without any lumen in the male striped dolphin. The reason is an inactive reproduction phase in this animal (even this animal died during the summer). Lumen of the seminiferous ehanells in bottlenosed dolphin was full of spermatozoa even this animal died during the winter. This findings agree with the literature eoneerning a sesonality of mating of the striped dolphin, opposite to the botthlenosed dolphin. Aeeording to the presenee of the different tissue elements, dolphin penis is of the fibro-elastie type like those of the domestic ruminants and swine.

Forestomach of striped dolphin have mucose layer without glands. Some multiple regulatory blood vessels arrangements were well developed in the liver and it was described in some other land mammals and some fishes, too. Pancreas of the striped dolphin was similar to those in bottlenosed dolphin. Langerhans islands were smaller than surrounding mucose glands.

Dorsal horn of the gray matter is less developed than ventral horn which was visible on the transverse sction of the medula spinalis. Neural cells of the brain shown very high positive reaction on the oxydative enzimes because of the many methabolic pathways for energy supply. Posterior pituitary was arranged around hypophisal stalk and ingrove like crura to surounding pituitary tissue. Antherior pituitary make majority of this organ. This relation of the antherior and posterior pituitary is simillar to those in dog and horse. Skeletal muscles were very positive in the oxydative enzymes, especially in glutamate dehidrogenase and even more succinate dehidrogenase. Intensity of those reactions showed high energy capacity of this cells with numerous mitohondria. Some rudimentary hair folicle was visible in the dermis of the skin.