

MENSTRUATION 



The process of menstruation, and the nutrition of the genital 

 organs, especially the uterus, are intimately dependent upon the 

 ovaries. There is good evidence that the influence is exerted through 

 an internal secretion formed by some portion of the ovarian sub- 

 stance. When, for instance, the ovaries of young animals (guinea- 

 pigs) are removed from their normal situation and transplanted to 

 a distant part of the body, the external genitals, vagina, and uterus 

 undergo the normal development instead of being arrested in their 

 growth, as is the case when the ovaries are removed altogether. The 

 removal of the ovaries in adult animals leads to fibrous degeneration 

 of uterus and Fallopian tubes. On the other hand, removal of the 

 i terus has no effect on the development of the ovaries in a young 

 animal, and does not cause degeneration of the ovaries of an adult 

 animal. In monkeys, in which a menstrual flow comparable to that 

 in the human female occurs, it was found that menstruation took 

 place after the ovaries had been transplanted from their original seat, 

 and the flow stopped when the transplanted ovaries were removed. 

 The view has been put forward that the important part of the ovary 

 for these functions is the corpus luteum, which is considered to be 

 a gland with an internal secretion (Born). This secretion seems 

 to be connected with the implantation of the ovum and the sub- 

 sequent growth of both ovum and uterus. According to Fraenkel, 

 the absence of the corpus luteum prevents implantation. The 

 experiments of Marshall and Jolly also indicate that the corpus 

 luteum forms some substance, which exerts an action on the uterine 

 mucosa, during the earlier stages of pregnancy. When the ovum 

 has not been fertilized the corpus luteum brings about menstruation. 

 Where fertilization has occurred it prepares the uterus for the im- 

 plantation of the ovum. It is generally considered that as regards 

 their origin there is no difference between the true and the false 

 corpora lutea. 



The mode of origin of the corpus luteum has given rise to much 

 discussion. Two chief views have been put forward: (i) That it is 

 a structure derived from certain large epithelium-like cells (theca 

 cells) in the connective-tissue wall (theca) of the discharged follicle 

 (v. Baer, et al.} ; (2) that it is developed from the follicular epithelium 

 (membrana granulosa) (Sobotta, et al.). The first view seems to be 

 best established. The theca cells multiply and grow into the cavity 

 of the discharged follicle. Their yellowish colour is due to the 

 presence in them of lipoid droplets. 



The influence of the ovary on the formation of the decidua has 

 been illustrated in a very interesting way by the investigations of 

 L. Loeb on the artificial production of deciduomata. He has shown 

 that if a number of incisions are made into the uterus of a rabbit or 

 guinea-pig within a certain interval after the cestral period (period of 

 heat), a structure with the histological characters of the decidua 



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