Comparative histomorphological study of the larynx, trachea and syrinx

Morphology and morphometrics of the upper respiratory tract in connection with the disciplines mentioned above constitute a significant contribution to the increase of the taxonomic analyses and phylogenetic relations between various avian species. also important for the ecological studies revealing an extreme heterogeneity among birds also in this respect.Respiratory system begins at the nares, passages in the head that lead to pump gas to the larynx. Trachea extends from the larynx and is sometimes very incompressible, as in ducks and geese to compress, as in chickens. Trachea in some birds is extremely long (sometimes longer than the entire body), and tortuous or coiled, as in the trumpet bird. The syrinx is partly tracheal and bronchial in origin and is highly variable in structure between species; it is composed of variable ossified cartilages, vibrating membranes, and muscles.the present study is to describe the basic morphological features and histological structures of larynx , trachea and syrinx in male and female of two species of aquatic birds (geese) and land birds(fowls), to determine the intraspecific and interspand interspecific differencebetween two species.