The completion of interstitial implantation, so that the conceptus is entirely within the endometrium, occurs: on about day 20 by about day 11 by the end of the first week by erosion of the myometrial lining as a result of endodermal proliferation
Both the neurenteric canal and the notochordal plate are present in the conceptus at the same time. true false
The amniotic cavity develops: on the tenth day within the outer cell mass within the inner cell mass near the
cytotrophoblast in extraembryonic mesoderm none of the above
During the second week of development, the trophoblast differentiates into: syncytiotrophoblast ectoderm intraembryonic mesoderm yolk sac (secondary)
Major events beginning in the second week of development include: notochord differentiation somite formation angiogenesis yolk sac development
The first two intraembryonic germ layers to differentiate are the: ectoderm & hypoblast epiblast & hypoblast ectoderm & endoderm ectoderm & mesoderm
The yolk sac in the human embryo: does not contribute to the embryonic gut is devoid of hemopoietic activity, or blood
cell formation is the site of primordial germ cell production stores nutrients throughout pregnancy
The bilaminar germ disc: consists of epiblast and mesoblast is derived from the outer cells of the morula forms the embryo proper synthesizes human chorionic gonadotropin,
HCG
The definitive yolk sac of the embryo appears by what day? 13th 26th 72nd 94th 2nd
The amniotic cavity appears as a slit-like space near the embryonic polar trophoblast and within the: extraembryonic mesoderm exocoelomic membrane inner cell mass connecting body stalk cytotrophoblast
During the second week, the embryonic disk is composed of: ectoderm ectoderm and mesoderm endoderm epiblast and hypoblast ectoderm, mesoderm and endoderm
The part of the 13-day embryoblast from which the embryo proper is formed: lies between the amniotic cavity and yolk sac also contributes to the roof of the yolk sac is composed of two primary germ layers is attached to the amnion all of the above are correct
The cloacal membrane consists of: embryonic endoderm, mesoderm and
ectoderm endoderm of the roof of the yolk sac and
embryonic ectoderm a spherical area of endoderm fused to
embryonic mesoderm the prochordal plate and the overlying
embryonic endoderm none of the above
The amniotic cavity develops: on the 10th day within the inner cell mass between inner cell mass and trophoblast in the extraembryonic mesoderm between two layers of cytotrophoblast
Which statement about the 14-day blastocyst is NOT true? villi are absent extraembryonic coelom surrounds the yolk
sac primitive uteroplacental circulation is
established extraembryonic mesoderm is split into two
layers none of the above
The ___________ gives rise to the extraembryonic mesoderm. ectoderm hypoblast blastocyst trophoblast syncytiotrophoblast cytotrophoblast blastocoele inner cell mass notochord prochordal plate primary yolk sac amniotic cavity intraembryonic coelom secondary yolk sac
Which layer of the bilaminar embryonic disc forms part of the lining of the amniotic cavity? epiblast hypoblast blastocyst trophoblast syncytiotrophoblast cytotrophoblast blastocoele inner cell mass notochord prochordal plate primary yolk sac amnioblast intraembryonic coelom secondary yolk sac
Which layer invades into the maternal endometrium and forms the lacunar network for placental-maternal exchange? blastocyst cytotrophoblast syncytiotrophoblast endoderm ectoderm mesoderm
Which layer is acellular, does not expand mitotically, and produces human chorionic gonadotropin (hCG) which stimulates progesterone production by the corpus luteum? syncytiotrophoblast cytotrophoblast epiblast endoderm ectoderm mesoderm
Which layer is cellular and expands mitotically into syncytiotrophoblast to form primary chorionic villi that can be used in chorionic villus sampling or genetic testing for the early fetus? syncytiotrophoblast cytotrophoblast epiblast endoderm ectoderm mesoderm
What malignant tumor arises from trophoblastic cells? Liposarcoma Rhabdomyosarcoma Fibroma Choriocarcinoma Endometrioma
How does a hydatidiform mole occur? Hyperplastic proliferation of trophoblast within the uterine wall Malignant transformation of endometrial cells Malignant transformation of ovarian cells Malignant proliferation of blastocyst