240 MANUAL OF HISTOLOGY. 



pertropliied and newly formed muscular elements undergo 

 retrograde development and fatty metamorphosis. 



The Fallopian tubes, or temporary ducts of the ovary, con- 

 sist of an external covering furnished by the peritoneum, rich 

 in connective tissue and blood-vessels ; a muscular coat made 

 up of an outside layer of longitudinal, and an inside layer of 

 circular involuntary muscular elements ; and, finally, an in- 

 ternal mucous membrane. A division of the tube is made into 

 two parts : that toward the uterus, into which it opens, the 

 much narrower portion, is the isthmus, while the free half is 

 the ampulla, which terminates in the fimbrice. The mucous 

 membrane, upon transverse section of the tube, in the narrow 

 portion, is seen thrown into simple longitudinal folds, while in 

 the ampulla the folds are much more complicated, and in a 

 transverse section have a dendritic appearance. The epithelium 

 covering the mucous membrane consists of ciliated columnar 

 epithelial cells. The movements of the cilia occasion a current 

 in the direction of the uterine opening. There is an absence of 

 glands in the mucous membrane of the Fallopian tubes. The 

 same histological elements are present in the fimbrise as in 

 other portions of the tube, of which they are a direct contin- 

 uation. 



The ovary for histological study may be divided into two 

 parts, the cortex and medullary substance ; covering the cor- 

 tex is a layer of columnar epithelial cells, named the ovarian 

 or germ epithelium (Fig. 107). In a perpendicular section, the 

 germ-epithelium is here and there seen to extend down into 

 the substance of the organ and form tubes the ovarial tubes. 

 The cortical substance or parenchymal zone consists of several 

 layers of dense connective tissue, in which are found ovarial 

 tubes and ovarian follicles. The most external follicles are im- 

 perfectly developed, while those lying deeper are more highly 

 developed and contain the ovum. Internal to the cortex is the 

 medullary substance or vascular zone, in which are numerous 

 blood-vessels, giving it the nature of a cavernous tissue. 



The stroma of the ovary consists of fibrillar connective tis- 

 sue. In the vascular zone it is somewhat loose in texture, and 

 contains a network of elastic tissue. There are also found in 

 this zone fasciculi of smooth muscular fibres, which follow the 



