ABSTRACT
EMBRYOLOGY OF THE GENITOURINARY SYSTEM 1. For each of the following structures, select its germinal layer of origin. (Each
answer may be used once, more than once, or not at all.) A. The nephric system B. Müllerian and wolffian ducts C. External genitalia
Options: a. Endoderm b. Mesoderm
c. Ectoderm
2. During embryonic development of the GU system, which one of the following is true? A. Male and female differentiation begins at the beginning of the second trimester. B. The default process for fetal differentiation is development of male external genitalia. C. The external genitalia for both sexes develop from the mesonephric ducts. D. The interstitial cells of Leydig produce a testosterone analogue that directs male
development. E. Müllerian inhibiting substance (MIS) activates the Sertoli cells to direct female
differentiation.
