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REPRODUCTION 



The Corpus Luteum 



When the ovum has been discharged the epithehal cells 

 which remain in the Graafian folhcle hypertrophy and 

 form a sohd mass of large cells containing a yellow pig- 

 ment — lutein — and separated by connective tissue which, 



Fig. G7. — Fully formed corpus luteum of moute(from Sobotta). The 

 luteal tissue is vascularised and the central cavity filled in with 

 connective-tissue (from Marshall, The Physiology of Reproduction). 



together with vessels, grows inwards from the outside 

 wall. This structure is called the corpus luteum. In 

 the centre there may be a clot of blood caused by the 

 rupture of the blood-vessels during ovulation. If preg- 

 nancy does not occur the corpus luteum in some animals 

 grows only for a short period, then atrophies. But if 

 conception takes place its growth continues until the middle 



