Nokea
A couple just learned they are expecting their first child and are curious if they are having a boy or a girl. At what point of development can the couple first expect to see the sex of their child on ultrasound?
- A. 4 weeks' gestational age
- B. 6 weeks' gestational age
- C. 10 weeks' gestational age
- D. 16 weeks' gestational age
Correct Answer: C
Rationale: The fetal period begins at the 9th week, and by the 10th week the external genitalia are visible to ultrasound examination.
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What complication can result from untreated respiratory distress in the newborn?
- A. Esophageal atresia
- B. Gastric dilation
- C. Cold stress
- D. Reopening of the foramen ovale
Correct Answer: D
Rationale: Respiratory distress can cause increased pressure in the right ventricle, causing reopening of the foramen ovale.
A woman missed her menstrual period 1 week ago and has come to the doctor's office for a pregnancy test. Which placental hormone is measured in pregnancy tests?
- A. Progesterone
- B. Estrogen
- C. Human chorionic gonadotropin
- D. Human placental lactogen
Correct Answer: C
Rationale: Human chorionic gonadotropin is the basis for most pregnancy tests. It is detectable in maternal blood as soon as implantation occurs, usually 7 to 9 days after fertilization.
A nurse is teaching a lesson on fetal development to a class of high school students and explains the primary germ layers. What are the germ layers? (Select all that apply.)
- A. Ectoderm
- B. Endoderm
- C. Mesoderm
- D. Plastoderm
- E. Blastoderm
Correct Answer: A,B,C
Rationale: The zygote transforms its embryonic disc into three layers: the ectoderm, the mesoderm, and the endoderm.
What part of the fetal body derives from the mesoderm?
- A. Nails
- B. Oil glands
- C. Muscles
- D. Lining of the bladder
Correct Answer: C
Rationale: The mesoderm is responsible for the development of muscles. Nails and oil glands derive from the ectoderm. The lining of the bladder derives from the endoderm.
During an ultrasound, two amnions and two placentas are observed. What will be the most likely result of this pregnancy?
- A. Dizygotic twins
- B. Monozygotic twins
- C. Conjoined twins
- D. High-birth weight twins
Correct Answer: A
Rationale: Dizygotic twins always have two amnions and two chorions (placentas).