272 VETERINARY STATE BOARD 



stalk, surrounded by the amnion, and includes the remnant of the 

 vitelline duct. For convenience of description, it may be divided 

 into an amniotic and an allantoic portion. The amniotic, the longer, 

 extends from the umbilicus of the f cetus, through the amniotic cavity, 

 to open into the cavity of the allantois. It contains the following 

 structures : the amnion, the two umbilical arteries, the two umbilical 

 veins which are sometimes fused into a single vessel, the urachus, 

 and the vestiges of the vitelline duct, besides Whartonian gelatin. 



The allantoic portion consists, for the most part, of the mass of 

 umbilical vessels; other structures found in it are the remnants of 

 the vitelline duct, and Whartonian gelatin. 



The umbilical cord forms a bond of communication between the 

 foetus and the placenta. 



Describe the position of the foetus in multiple pregnancy. 



Each foetus may have its own amnion and chorion, or each may 

 have its own amnion, but the same chorion. Occasionally, in twin 

 pregnancies, one foetus is more or less enclosed within the body of 

 the other. 



In ruminants (cow and ewe) each of the twin foetuses usually 

 occupies one cornua of the uterus and presents with the head toward 

 the OS uteri ; although occasionally they present alternately, that is, 

 one anteriorly and the other posteriorly. 



What is the liquor amnii ? Give its functions in pregnancy and during 

 labor. 



The liquor amnii is an albuminous alkaline fluid, found in the 

 amniotic sac, in which the foetus is suspended. It contains about 

 99 per cent, of water, as well as albumin, sugar, urea, and other 

 urinary products, also meconium. The amount of the fluid in the 

 mare and cow varies from 5 to 6 litres. 



During pregnancy, it is useful in: 1. Preserving an equable 

 temperature for the foetus. 2. Protecting the skin of the foetus. 

 3. Favoring movements of the foetus by equalizing pressure. 4. Pre- 

 venting injuries of the foetus from external movements. 5. Protect- 

 ing the mother from injury by fetal movements. 



During labor, it protrudes the membranes and dilates the os uteri, 

 protects the foetus from violent uterine contractions, and lubricates 

 the vagina, thus facilitating passage of the foetus through it. 



Mention the four stages in the process of sexual generation. 

 Copulation, fecundation, gestation, and parturition. 



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