Abstract
Nerve plexus is formed in the hilus ovarii of dog, but this is far poorer than that in man in development. The nerve elements there consist of numerous thin vegetative fibres and a small number of thick sensory fibres. Perivascular plexus is found along the walls of blood vessels, especially of the arteries in the hilus.
The small nerve bundles running through the hilus into the medulla branch out into finer branches, which ramify and come into mutual anstomisis to form intramedullar plexus. This plexus is also poorer in size than that in man.
Vegetative fibres originating in the intramedullar plexus are found also running into the cortex. These diffuse widely in the cortex and are quite larger in number in dog than in man.
The terminations of vegetative fibres are represented by STÖHR'S terminal reticula in a canine ovary too. For example, the vegetative fibres running along the blood vessels in the ovary, which have been described as ending in free terminations, always pass through preterminal fibres over into terminal reticula, as in perivascular vegetative fibres in all the other parts of the body. The terminal reticula always make ramifications and anastomoses with each other, forming a large system of net-works. They contain SCHWANN's nuclei here and there and stand in tactile control over the supplied cells.
A few vegetative fibres are found running into the tunica albuginea which are well developed in the parts approaching the mesoovarium. These form their terminal reticula in the connective tissue and sometimes directly beneath the germinal epithelial cells in these parts, which however, never penetrate into the epithelial cells. Where the epithelial bladders originating in the germinal epithelium are in good development, the connective tissue between the bladders is very poorly developed, but in some rare cases, terminal reticula are formed in this tissue too.
Nerve supply to the primary follicles in the cortex is richer in the canine than in the human ovaries. Their terminal reticula run along the outside of the follicle cell layer, but unlike in human ovary as described by SAKAGUCHI, they never run into the follicle cell layer.
The nerve supply to the egg follicles in the course of growth and provided with stratum granulosum is also much better developed in dog than in man, the thecae folliculi containing a rather large quantity of vegetative fibres. These also end in terminal reticula and come into control over the connective tissue cells as well as the small blood vessels and the capillaries. A part of the terminal reticula penetrates as far as into the basal layer of the stratum granulosum.
Atretic follicles are rather limited in number in dog's ovaries, and this may be due to the better nerve supply to the egg follicles in dog than in man. Vegetative nerve elements are also found running into these follicles, especially often in company with the newly blood vessels or capillaries. They also end in terminal reticula.
Well-developed terminal reticula are formed in the connective tissue containing blood vessels and blood capillaries in the medullar substance. Fine fibres are also found running into the rete ovarii, their terminal reticula sometimes being formed on the outside of the epithelial cells layer. Terminal reticula are found also around the medullar cords existing especially abundantly in the peripheral parts of the medulla. But the development of the terminal reticula around such epithelial ducts is by no means good and of course no terminal reticulum is found to penetrate into the epithelial cells.
Sensory terminations have been discovered in the ovaries of dog as in man. Here, the trunk fibres, after losing their myelin, end in sharp or blunt points without branching or after branching out into 2 or 3 rami. That is, their terminations are either of the unbranched or the simple branched type, which are formed in the medulla
