HISTOLOGY. 



Amnion. 



Com pa 





4- Gland. 



Cavernous layer. <r 



Muscularis. 





FIG. 347. VERTICAL SECTION THROUGH THE WALL OF A UTERUS ABOUT SEVEN MONTHS PREGNANT, 

 WITH THE FETAL MEMBRANES IN SITU. Between amnion and chorion are threads of gelatinous 

 connective tissue. X 30. (Schaper.) 



without glands. 



FIG. 348. DECIDUAL CELLS FROM THE 

 Mucous MEMBRANE OP A HUMAN 

 UTERUS ABOUT SEVEN MONTHS 

 PREGNANT. Below a "giant- 

 cell," above to the right a cell 

 with a karyokinetic figure. X 

 250. (Schaper.) 



The cells of the tunica propria have enlarged, and become 

 decidual cells (Fig. 348). These cells which 

 occur only in pregnancy are flattened, round, 

 oval or branched structures of large size (.03 

 to o.i mm.). Usually they contain a single 

 nucleus but often there are two or more, and 

 in giant forms there may be 30 or 40. The 

 cavernous layer of the mucosa contains slen- 

 der clefts parallel with the muscularis. 

 These are glands which have been stretched 

 laterally; some of them retain areas 

 of normal epithelium, but in many 

 the epithelium has degenerated and from 

 some it has wholly disappeared. The con- 

 nective tissue is but slightly modified. 

 Throughout the decidua but especially in 

 the superficial portion, the vessels are 

 greatly distended. 



