THE HORMONES IN HUMAN REPRODUCTION 



them and keep them while they develop, the mammary gland 

 must be signaled to grow and prepare milk for them when 

 they are born. The ovary still has ahead of it the task of 

 getting these things done. 



The Graafian follicle therefore does not shrivel away after 

 shedding the egg. Indeed, it has scarcely had time to collapse 



The corpus luteum inthe ovaries of rabbitpl^A monkey 



^Corpora lutea 



Corpus 

 luteuKi 



Life cycle of the corpus luteum (diagrammatic sections) 

 ess 



Old Corp. lut 



Ripe follicle 



.-^MXed ->. Solid, . 

 follicle corpus lut. 



Fig. 9. Diagram illustrating the structure and history of the corpus 

 luteum. 



before it is being transformed into a corpus luteum (Fig. 9) 

 and begins to function as an organ of internal secretion for 

 the benefit of the embryo. The accompanying illustrations 

 (Plate IX) give an idea of the situation and appearance of 

 the corpus luteum. This remarkable change is brought about 

 by growth of the cells that lined the cavity, which become so 

 much larger that the inner wall of the follicle, folded by its 

 collapse, becomes thick and firm and converts itself into a 



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