Tlir: REPRODUCTIVE SYSTEM 



375 



b -tf 







The blood-vessels, especially the capillaries and veins, become greatly 

 distended, thus contributing largely to the increase in thickness of 

 the mucosa. There are also proliferation of the connective-tissue 

 cells, an increase in the number of leucocytes, and a growth of the 

 uterine glands. The surface at the same time becomes irregular, the 

 glands opening into deep pits or 

 depressions, and the glands them- 

 selves become more tortuous and 

 their lumina more widely open. 

 The mucous membrane has now 

 reached a thickness of about 6 

 mm., and is known as the de- 

 cidua menstrualis (Fig. 267). 



{h) The Stage of Men- 

 struation Proper. — This is 

 marked by the escape of blood 

 from the engorged vessels and 

 the appearance of the external 

 phenomena of menstruation. 

 The blood escapes partly by rup- 

 ture of the vessel walls, partly by 

 diapedesis. The hemorrhage is 

 at first subepithelial, but the 

 epithelium soon gives way and 

 the blood escapes into the cavity 

 of the uterus. Much difference 

 of opinion exists as to the amount 

 of epithelial destruction during 

 menstruation, some claiming 

 that the entire epithelium is de- 

 stroyed with each menstrual period, others that the epithelium re- 

 mains almost intact. Complete destruction of the epithelium is 

 hardly compatible with the restoration of the epithelium which always 

 follows menstruation. While there is undoubtedly destruction of 

 most or all of the surface epithelium and of the glands to some con- 

 siderable depth, the deeper portions of the glands always remain to 

 take part in the succeeding regenerative phenomena. 



(c) The Stage of Reparation. — x\fter from three to five days 

 the bleeding from the uterine mucosa ceases and the return to the 

 resting condition begins. This is marked by disappearance of the 



Fig. 267. — Section through Mucous 

 Membrane of Virgin Uterus during First 

 Da}' of Menstruation. X30. (Schaper.) 

 a, Surface epithelium; b, disintegrating 

 surface; c, pit-Hke depression in mucous 

 membrane; d, excretory duct; e, blood- 

 vessels; ,(j, gland tubule; //, dilated gland 

 tubule; ;«, muscularis. 



m 



