On the Fine Structure of Urogenital Organs in Male Rabbit

Abstract

The urogenital organs examined in our study of rabbit were found to show rather widely different constructions from those in man and other mammals examined in the past. The ductus deferentes of both sides run side by side down to the basal part of the urinary bladder, next along the dorsal side of the urethra, swell out into the ampullae and finally open out into the distal part of the sac-like single seminal vesicle found on the dorsal side of the ampullae. The distal end of the seminal vesicle runs a little further distalwards, before opening out into the urethra. The prostata is situated further dorsal to the seminal vesicle and its distal portion extends farther so the vicinity of the COWPER's glands. The ampullae of the ductus deferentes, the seminal vesicle, the prostata and the COWPER's glands were found to show a rather peculiar histology.If the sinus urogenitalis adjoining the distal end of the urethra in the strict sense may be included under the name of urethra, the urethra in this wider sense of rabbit consists of the following 4 parts: 1) The proximalmalmost part down to the orifice of the seminal vesicle into the urethra (pars ampullovesicalis urethrae, as we wish to call it); 2) The next proximal part accompanied only by the prostate gland (the pars prostatica nrethra); 3) The distal part accompanied by the COWPER's glands and the m. urethralis (the pars muscularis urethrae) and 4) The distalmost part running through the penis body (the pars cavernosa urethrae). The denomination of the“pars cavernosa”, however, is particularly well befitting only to the urethral portion running through the radical part of the penis body, for in this part alone typical cavernous plexus is in notably good development, the more distal parts of the penis body containing only some veins of considerable diameter instead of such a plexus.The urethra is rich in mucous folds and is lined by a transitional epithelium in the proximal part, but in other parts, the epithelium is engerally of a two-rowed cylindrical type; in the foremost part of the urethra with dilated lumen, corresponding to the fossa navicularis, the epithelium is a stratified flat epithelium, which passes over into the thin stratified flat epithelium of mucous nature covering the glans penis. The propria of the urethra is in most parts rather thick and contains a large number of fine longitudinal smooth muscle bundles. The corpus cavernosum penis resembles rather that of man in construction, but as in some other mammals, its tip protrudes into the glans penis.