The primordial germ cells that eventually from , the oogonia and spermatogonia originate in which of the following
Correct Answer: Endodermal lining of the yolk sac
Description: The primordial germ cells are first seen in the endodermal lining of the wall of the yolk sac (derived from the hypoblast) at the end of the third or beginning of the fourth week in the region of the allantois. During embryonic folding, the dorsal part of the yolk sac is incorporated into the embryo as the primitive gut. The primordial germ cells subsequently migrate along the dorsal mesentery of the hindgut and into the gonadal (genital) ridge by week 6. The primary sex cords grow into the mesenchyme underlying the ridge, and the primordial germ cells become incorporated into the primary sex cords. The chorion is the outermost fetal membrane and is composed of extraembryonic somatic mesoderm, cytotrophoblast, and the syncytiotrophoblast. It is divided into the chorion frondosum, where the villi form and proliferate. and the smooth chorion, also known as the chorion laevae. The following diagram illustrates the arrangement of the fetal membranes.
Category:
Unknown
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now