Moore: The Developing Human, 10th Edition

Directions: Each group of questions below consists of a numbered list of descriptive words or phrases accompanied by a diagram with certain parts indicated by letters or by a list of lettered headings. For each numbered word or phrase, select the lettered part or heading that matches it correctly and then insert the letter in the space to the right of the appropriate number. Sometimes more than one numbered word or phrase may be correctly matched to the same lettered part or heading. 1. Extraembryonic coelom a. A b. B c. C d. D e. E 2. Cytotrophoblast a. A b. B c. C d. D e. E 3. Lacunar network a. A b. B c. C d. D e. E ANS: A The lacunar networks form by coalescence of lacunae in the syncytiotrophoblast. As the maternal sinusoids are eroded, blood seeps into these networks. Nutrients in the embryotroph diffuse through the two layers of tropNhoUbRlaSstIaNndGpTaBss.tCo OthMe embryo by way of the extraembryonic coelom. 4. Epiblast forms its floor a. A b. B c. C d. D e. E ANS: B The floor of the amniotic cavity is formed by the epiblast. The amnion enclosing the amniotic cavity is attached to the epiblast of the embryonic disc. Initially, some amniotic fluid may be secreted by the amniotic cells, but most of it is derived from the maternal blood. 5. Develops as a localized thickening of hypoblast a. Corpus luteum b. Zona pellucida .......................................CONTINUED............................