CHAPTER VII. 



STUDY OF THE UTERUS AND THE FCETAL APPEN- 

 DAGES OF MAN. 



Histology of the Uterus. 



In most mammals the uterus is double. This is the case in the pig, the 

 rabbit, and the mouse, the three species which furnish material for the practical 

 study as planned in this book. In these animals each uterus is a long, more or 

 less cylindrical tube. In primates the double uterus exists only during very 

 early embryonic stages, after which the two are found united into a single median 

 uterus. The mammalian uterus is always lined by a mucous membrane, con- 

 sisting of a superficial epithelium, which forms glands, and of a deeper layer of 

 reticulate connective tissue, in which there are lymph spaces, nerves, and a fairly 

 abundant blood-supply. The mucous membrane is subject to very marked 

 periodic changes in structure. It is enclosed by the muscular layers of the organ, 

 the muscle-fibers being of the smooth type. In animals with double uteri the 

 muscle-fibers form two distinct layers, an inner circular and an outer longitudinal 

 layer. In the primate uterus the disposition of the fibers is far more compli- 

 cated, and the two distinct layers cannot be identified. The surface of the uterus, 

 wherever it is free, is covered by a layer of peritoneum which consists of a layer 

 of flattened epithelial cells and a thin underlying layer of fibrillar connective 

 tissue. 



The human uterus at birth has a mucosa which is about 0.2 mm. thick. 

 The mucosa is soft, pale gray or reddish-gray in color; it consists of a covering 

 of ciliated epithelium and a connective- tissue layer. It is without glands, the 

 glands not appearing usually until the third or fourth year, and developing very 

 slowly up to the age of puberty. 



Menstruation. 



The function of menstruation involves great changes in the mucosa of the 

 body of the uterus. We distinguish three periods : (i) tumefaction of the mu- 

 cosa, with accompanying structural changes, taking five days, or, according to 

 Hensen, ten days; (2) menstruation proper, about four days; (3) restoration of 



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