Chapter 2: Fetal Gas Exchange and Circulation
1. Which of the following embryonic germ layers gives formation to the respiratory system?
The respiratory system—pharynx, lungs, and epithelial lining of the trachea and
lungs—originates in the endoderm. Refer to Box 2-1 in the textbook to see the list of various
tissue systems found in the three embryonic layers.
REF: p. 13
2. What is the function of Wharton’s jelly inside the umbilical cord?
a. To help provide nutrition to the fetus
b. To prevent the vessels inside the cord from kinking
c. To help protect the fetus
d. To regulate the temperature between the fetus and the mother
Wharton’s jelly, a gelatinous substance inside the umbilical cord, helps protect the vessels of
the fetus and may prevent the cord from kinking.
REF: p. 13
3. Which of the following organs is considered to be the first to form?
The heart is considered to be the first complete organ formed. By 8 weeks of gestation, the
normal fetal heart is fully functional, complete with all chambers, valves, and major vessels.
REF: p. 14
4. A pregnant woman is coming for an early prenatal evaluation and wants to know if she can
listen to the baby’s heartbeat. How early can the fetal heartbeat be detected?
a. Day 8
b. Day 22
c. Day 45
d. Day 60
By day 22 cardiac contractions are detectable and bidirectional tidal blood flow begins.