QUESTIONS AND ANSWERS 265 



Define the corpus luteum. Describe the changes in the ovary after 

 fecundation. 



The corpus luteum, or "yellow body," is a yellow mass in the 

 ovary in the place of an ovisac which has discharged its ovum. If 

 the ovum has been impregnated, the corpus luteum grows and lasts 

 for several months, usually throughout pregnancy. If impregnation 

 has not taken place, the corpus luteum degenerates and shrinks. 



After fecundation of the ovum, segmentation occurs. The ovum 

 divides into halves, each half subdivides, etc., forming a spherical 

 mass known as the morula. 



Define (a) a true corpus luteum, (b) a false corpus luteum. 



If the ovum has been impregnated, the corpus luteum grows and 

 lasts for several months and is called a ' ' true corpus luteum. ' ' If 

 impregnation has not taken place, it degenerates and shrinks and is 

 called a "false corpus luteum." 



Describe the corpus luteum in the cow and the sow. 



See preceding answers. The ovisac is filled with lymph and 

 blood, projects beyond the ovarian surface, and is deep yellow in 

 color in the cow, and a yellowish-brown color in the sow. 



Give the cause of menstruation. 



Not definitely known. It is thought to be due to the shedding 

 of the epithelium of the mucous membrane of the uterus. This ex- 

 poses the tunic of the capillaries, causing them to rupture because 

 of their distended condition. 



Is the menstrual flow independent of the influence of the ovaries? 

 Explain. 



No. There is a close bond of sympathy between the ovaries and 

 the uterus, which defies explanation. It is well known that, after 

 removal of the ovaries, menstruation ceases to occur. 



Define embryology, embryotomy, hydrocephalus. 



Embryology is the science which treats of the development of the 

 embryo. 



Embryotomy refers to the cutting up of a foetus to facilitate 



delivery. 



Hydrocephalus is a fluid effusion within the cranium. 



Name the female generative organs and state the function of each. 

 Ovaries: generate ova. 



Oviducts: serve to convey the ova from the ovaries to the uterus 

 and spermatozoa to the ovary. 



