556 



FEMALE ORGANS OF GENERATION. [CHAP. XXXVIII. 



layers are not very clearly defined. The outermost layer is very 

 thin, and is incorporated with the sub-peritoneal tissue. It con- 

 sists of longitudinal and transverse fibres, many of the latter, after 

 investing the anterior and posterior surfaces of the organ, lose 

 themselves upon the Fallopian tubes, or enter the broad and round 

 ligaments. The middle layer makes up the greater part of the 

 thickness of the uterine walls, and consists of strong bundles; 

 which also run, some in a longitudinal and others in a transverse 

 direction. It is in this layer that the greater number of the ves- 

 sels which supply the organ, and which become so enormously 

 developed in pregnancy, ramify. The innermost layer is thinner, 

 and composed chiefly of thin longitudinal fibres. 



Round the external os uteri, the transverse fibres are very 

 abundant, and collected together beneath the mucous membrane, 

 so as to form a sphincter muscle. 



In these different layers, in the virgin uterus, the muscular fibre- 

 cells for the most part are seen as short spindle-shaped cells, in 

 Fig. 267. many of which, oval elongated nuclei can 



be demonstrated. At this, period, the 

 cells are often seen to be of very irre- 

 gular form, and are not always very 

 readily made out. The muscular fibre- 

 cells undergo increased development in 

 the pregnant state, and towards the end 

 of this period, will be found to be v 

 long cells with a distinct oval nucleus. 

 The cell terminates in long thin and 

 pointed extremities (fig. 266) . After de- 

 livery, these cells again diminish in dimen 

 sions, a number of fat globules appear i 

 their interior, and ultimately they regain 

 their former appearance (fig. 267); while, 

 at the same time, the entire organ returns 

 to its former volume. 



The mucous membrane of the uterus 

 forms a pale and not very thick lining 

 membrane. In the fundus and body of 

 the organ, it is of a redder colour than 

 in the cervix, in consequence of the greater vascularity of this 

 part. 



The epithelium is of the ciliated variety. 



Inbedded in the mucous membrane of the uterus are nume- 



Muscular fibre cells from the 

 uterus, three weeks after parturi- 

 tion, showing the fat globules in 

 their interior. The four cells to the 

 left have been treated with acetic 

 acid. After KOlliker. 



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