Histology and Innervation of Testicle, Spermatic Ducts, Urinary Bladder and Urethra of Snapping Turtle

Abstract

The testicles of snapping turtle are located close to the medial edges of the kidneys and are oval in form. The hilus testis is connected with the duplicated peritoneal mesorphium. A loose connective tissue of considerable thickness lies between the tubuli contorti testis. The tubuli contorti become tubuli recti upon reaching the hilus and then unite into a single duct.
The proper nerves coming into the testis run through the mesorchium into the parenchyma testis. They mainly consist in fine vegetative fibres but a small number of thick sensory fibres are also found intermingled. The vegetative fibres always end in STÖHR's terminal reticula. The sensory fibres, unlike in mammals, always end in the intertubular connective tissue of the parenchyma testis. Their terminations are very simple, consisting mainly in unbranched terminations and sometimes in simple branched terminations with terminal branches running out rather long wavy or looped courses. The terminal fibres sometimes run close up to the tubuli contorti but never penetrate into their spermatic epithelium.
The 1st spermatic duct originating in the hilus testis runs through the mesorphium and then lateralwards through the subserosa covering the corpus suprarenale and then joins the peculiarly constructed 2nd spermatic duct that runs downwards through the loose connective tissue layer formed in the middle part of the ventral side of the kidney. The 1st spermatic duct is a fine duct lined by a one-rowed cubic epithelium and covered by a layer of unstainable connective tissee. The 2nd spermatic duct is small in size and covered by a layer of circularly running spindlelike fibrocytes staining reddish at its incipient part, but the very long-extended 2nd spermatic duct proper has a wide lume, is lined by a one-rowed cubic epithelium, has a well-developed connective tissue circular layer around it and is covered on the outermost side by a longitudinal smooth muscle layer. In the loose connective tissue around it are found very numerous fine aberrant ductuli.
Nerve plexus is formed here and there in the loose connective tissue around the 2nd spermatic duct. This consists of many vegetative fibres and a few sensory fibres and send out nerve branches toward the 1st spermatic duct and the testicle.
The terminations of these sensory fibres are very simple in formation and are only sparse in the 1st spermatic duct and the proximamlmost part of the 2nd spermatic duct. But in the 2nd spermatic duct proper, the number of the terminations grows the larger, as we go down the further and beside the simple branched type, some instances of branched terminations are also found. Such branched terminations are particularly frequent around the 2nd spermatic duct in the part where it runs along the urethra and is free of the accompanying aberrant canaliculi.
Upon passing over into the ductus ejaculatorius, it runs along the lateral side of the anal canal and finally opens out into the anal canal. This duct grows smaller in size distalwards. It is lined by a one-rowed cylindrical epithelium and the longitudinal muscle layer around the circular connective tissue layer covering it becomes slowly poorer in development as the duct goes distalwards.
A rather large number of sensory fibres are found around the ductus ejaculatorius, forming their terminations around or inside the muscularis and in the subepithelial connective tissue. The termination are of the unbranched or the simple branched type and the terminal fibres often run out complex courses.
The epithelium of the urinary bladder is a strataified cylindrical one and the muscularis covering the outside of the propria mucosae is considerably well developed, forming a circular layer in most places but in some places forming a lonigtudinal one. The muscularis is covered on its outside by the submucosa and the serosa.