354 THE GENITOURINARY ORGANS. 



phosis result in a liquefaction of the cell-body, and finally lead to 

 a hyaline swelling, which renders the substance of the cell homo- 

 geneous. The zona pellucida softens, increases in volume, becomes 

 wrinkled, and after some time is absorbed. A further stage in 

 the regressive process consists in the formation of scar tissue, as 

 in the case of the corpus luteum. Here leucocytes accompany 

 the proliferation from the tunica interna of the theca folliculi, and 

 assist in absorbing the products of degeneration, the result being 

 a connective-tissue scar (vid. G. Ruge, and Schottlander, 91, 93). 



The blood-vessels of the ovary enter at the hilum and branch 

 in the medullary substance of the ovary. From these medullary 

 vessels branches are given off which penetrate the follicular zone, 

 giving off branches to the follicles and terminating in a capillary 

 network in the tunica albuginea (Clark, 1900). The relations of 

 the branches to the follicles are such that in the outer layer of the 

 theca folliculi the vessels form a network with wide meshes while 

 the inner layer contains a fine capillary network. The veins are of 

 large caliber and form a plexus at the hilum of the ovary. 



The lymphatics of -the ovary are numerous. They begin in 

 clefts in the follicular zone, which unite to form vessels lined by 

 endothelial cells in the medulla. They leave the ovary at the 

 hilum. 



The nerves accompany and surround the blood-vessels, while 

 very few nerve-fibers penetrate into the theca folliculi ; those doing 

 so form a network around the follicle and end often in small nodules 

 without penetrating beyond the theca itself. Ganglion cells of the 

 sympathetic type also occur in the medulla of the ovary near the 

 hilum (Retzius, 93 ; Riese, Gawronsky). 



3. THE FALLOPIAN TUBES, UTERUS, AND VAGINA. 



The Fallopian tubes or ova ducts consist of a mucous mem- 

 brane, muscular coat, and peritoneal covering. 



The mucous membrane presents a large number of longitudinal 

 folds which present numerous secondary folds which frequently 

 communicate with one another. Very early in the development 

 four of these folds are particularly noticeable in the isthmus ; these 

 may also be recognized at times in the adult. These are the 

 chief folds, in contradistinction to the rest, which are known as 

 the accessory folds (Frommel). The accessory folds are well 

 developed in the isthmus, and are here so closely arranged that 

 no lumen can be seen with the naked eye. The epithelium 

 lining the tubes is composed of a single layer of ciliated columnar 

 cells which entirely cover the folds as well as the tissue between 

 them. Glands do not occur in the oviducts, unless the crypts 

 between the folds may be considered as such. The mucosa 

 beneath the epithelium contains relatively few connective-tissue 



