Embryology Practice Questions With Answers Study Guide Questions And Correct Answers

9. The most common site for implantation in ectopic pregnancy is: A. internal os of the uterus B. mesentery C. ovary D. uterine tube E. other {Ans: D. is correct. The most common site of ectopic implantation is the uterine tube. The growth of the embryo in this site usually causes rupture of the tube and severe hemorrhage in the mother. Abdominally, an ectopic pregnancy often occurs in the rectouterine pouch, an area between the uterus and the rectum.}59. The following are true statements with regard to the fetal circulation EXCEPT: A. Since the fetal liver is a hemopoietic organ, it is large and well supplied with oxygenated blood. B. Fetal brain receives relatively pure arterial blood. C. Fetal and maternal blood vessels anastomose in the placenta D. In early developmental stages, one pulmonary vein buds from the left atrium of the heart. E. Foramen primum of the interatrial septum closes after the formation of the foramen secundum. {Ans: C. is correct. In the placenta, there is no anastomosis between the maternal and fetal vessels. Maternal blood from the spiral arteries enters the cotyledons, where it bathes the villi from the fetus. This all occurs without anastomosis.}10. With