GENERAL EMBRYOLOGY 



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there are many large spherical cells, called the decidual cells. These 

 cells are present throughout the whole thickness of the decidua vera, 

 but they are most numerous in its superficial stratum. 



The decidua vera is composed of three layers — namely, stratum 

 compactum, stratimi spongiosum, and stratum profundum. 



The stratum compactum is the superficial layer, and lines the 

 uterine cavity. The uterine glands, as they traverse it, are elon- 

 gated, somewhat dilated, slightly tortuous, and parallel with each 

 other. The epithehum Uning them consists of cubical or flat cells. 



Decidua Serotina 



Fundus Uteri 



Cotyledon 

 Villi of Chorion 

 Froodosum 



Chcrioo Frondosum 



F.mbryo and Allantoic Stalk 



Fallopian Tube- 



Decidua 



Chorion 



Os Internum 

 Cavity of Cervix 



Os Externum 



Fig. 674. — The Gravid Uterus. 



This stratum contains many decidual cells, and has a compact 

 structure. 



The stratum spongiosum, or cavernosum, is more deeply placed than 

 the stratmn compactum. The uterine glands, as they traverse it, 

 are much dilated, and very tortuous. It contains few decidual 

 cells, and has a spongy or cavernous structure. As seen in section 

 it presents a number of irregular spaces, or areolae, which represent 

 the gland-cavities. The epithelium lining these cavities consists of 

 cubical or flat cells. 



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