Block 7 BRS - Placenta And Amniotic Fluid
- 1.
During the later stages of pregnancy, maternal blood is separated from fetal blood by
- A.
Syncytiotrophoblast only
- B.
Cytotrophoblast only
- C.
Syncytiotrophoblast and cytotrophoblast
- D.
Syncytiotrophoblast and fetal endothelium
- E.
Cytotrophoblast and fetal endothelium
Correct Answer
D. Syncytiotrophoblast and fetal endotheliumExplanation
During the later stages of pregnancy, the placental membrane becomes very thin and consists of two layers, the syncytiotrophoblast and fetal endothelium.Rate this question:
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- 2.
The maternal and fetal components of the placenta are
- A.
Decidua basalis and secondary chorionic villi
- B.
Decidua capsularis and secondary chorionic villi
- C.
Decidua parietalis and tertiary chorionic villi
- D.
Decidua capsularis and villous chorion
- E.
Decidua basalis and villous chorion
Correct Answer
E. Decidua basalis and villous chorionExplanation
The placenta is a unique organ in that it is a composite of tissue from two different sources,
the mother and the fetus. The maternal component is the decidua basalis, and the fetal component is the villous chorionRate this question:
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- 3.
The intervillous space of the placenta contains
- A.
Maternal blood
- B.
Fetal blood
- C.
Maternal and fetal blood
- D.
Amniotic fluid
- E.
Maternal blood and amniotic fluid
Correct Answer
A. Maternal bloodExplanation
The intervillous space contains only maternal blood as the spiral arteries of the
endometrium penetrate the outer cytotrophoblast shell.Rate this question:
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- 4.
A young insulin-dependent diabetic woman in her first pregnancy is concerned that her daily injection of insulin will cause a congenital malformation in her baby. What should the physician tell her?
- A.
Insulin is highly teratogenic; discontinue treatment
- B.
Insulin does not cross the placental membrane
- C.
Insulin crosses the placental membrane but is degraded rapidly
- D.
Insulin will benefit her baby by increasing glucose metabolism
- E.
Insulin crosses the placental membrane but is not teratogenic
Correct Answer
B. Insulin does not cross the placental membraneExplanation
Insulin, like all protein hormones, does not cross the placental membrane in significant
amounts.Rate this question:
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- 5.
What is a normal amount of amniotic fluid at term?
- A.
50 mL
- B.
500 mL
- C.
1000 mL
- D.
1500 mL
- E.
2000 mL
Correct Answer
C. 1000 mLExplanation
The normal amount of amniotic fluid at term is 1000 mL. However, the amount of amniotic
fluid at various stages of pregnancy can be indicative of congenital malformations.
Oligohydramnios (400 mL in late pregnancy) may be indicative of renal agenesis.
Polyhydramnios (2000 mL in late pregnancy) may be indicative of either anencephaly or
esophageal atresia.Rate this question:
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- 6.
Which of the following does not pass through the primitive umbilical ring?
- A.
Allantois
- B.
Amnion
- C.
Yolk sac
- D.
Connecting stalk
- E.
Space connecting the intraembryonic and extraembryonic coeloms
Correct Answer
B. AmnionExplanation
The amnion does not pass through the primitive umbilical ring. As craniocaudal folding
occurs, the amnion becomes the outer covering of the umbilical cord.Rate this question:
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- 7.
Which of the following best describes the placental components of dizygotic twins?
- A.
One placenta, two amniotic sacs, one chorion
- B.
One placenta, two amniotic sacs, two chorions
- C.
Two placentas, two amniotic sacs, one chorion
- D.
Two placentas, two amniotic sacs, two chorions
- E.
One placenta, two amniotic sacs, two chorions
Correct Answer
D. Two placentas, two amniotic sacs, two chorionsExplanation
Dizygotic twins and 35% of monozygotic twins have two placentas, two amniotic sacs, and
two chorions (i.e., 222).Rate this question:
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- 8.
A 26-year-old pregnant woman experiences repeated episodes of bright red vaginal bleeding at week 28, week 32, and week 34 of pregnancy. The bleeding spontaneously subsided each time. Using ultrasound, the placenta is located in the lower right portion of the uterus over the internal os. What is the diagnosis?
- A.
Hydatidiform mole
- B.
Vasa previa
- C.
Placenta previa
- D.
Placental abruption
- E.
Premature rupture of the amniochorionic membrane
Correct Answer
C. Placenta previaExplanation
A placenta implanted in the lower part of the uterus near the internal os is called placenta
previa. The repeated episodes of bright red vaginal bleeding are caused by the gradual dilation of
the uterus in the later stages of pregnancy. As the uterus dilates, spiral arteries and veins supplying the placenta are ruptured. The mother may bleed to death, and the fetus is placed in jeopardy because of the compromised maternal blood flow.Rate this question:
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- 9.
A 19-year-old woman in week 32 of a complication-free pregnancy is rushed to the emergency department because of profuse vaginal bleeding. The bleeding subsides, but afterwards no fetal heart sounds can be heard, indicating intrauterine fetal death. The woman goes into labor and delivers a stillborn infant. On examination of the afterbirth, a velamentous placenta is detected. Although not much can be done at this point, what is the diagnosis?
- A.
Placenta previa
- B.
Vasa previa
- C.
Hydatidiform mole
- D.
Premature rupture of the amniochorionic membrane
- E.
Amniotic band syndrome
Correct Answer
B. Vasa previaExplanation
A velamentous placenta occurs when umbilical blood vessels abnormally travel through the
amniochorionic membrane before reaching the placenta proper. If the vessels cross the internal
os, a serious condition called vasa previa exists. As the fetus grows during pregnancy and the
amniochorionic membrane stretches, the umbilical vessels may rupture. When that happens, the
fetus will bleed to death. The mother is in no danger of bleeding to death in vasa previa because
only the umbilical vessels rupture.Rate this question:
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- 10.
Human chorionic gonadotropin (hCG) is produced by which of the following?
- A.
Ectoderm
- B.
Cytotrophoblast
- C.
Decidua basalis
- D.
Syncytiotrophoblast
- E.
Mesoderm
Correct Answer
D. SyncytiotrophoblastExplanation
The syncytiotrophoblast produces hCG.Rate this question:
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- 11.
A reliable index of fetal-placenta function is maternal urinary levels of
- A.
Estrone
- B.
Human placental lactogen (hPL)
- C.
Prolactin (PRL)
- D.
Progesterone
- E.
Estriol
Correct Answer
E. EstriolExplanation
Maternal urinary levels of estriol have long been recognized as a reliable index of fetalplacental function because estriol production is dependent on a normal-functioning fetal adrenal cortex, fetal liver, and placenta.Rate this question:
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- 12.
The Doppler fetal heart rate is first audible in which of the following trimesters?
- A.
First trimester
- B.
Second trimester
- C.
Third trimester
Correct Answer
A. First trimesterExplanation
The fetal heart rate is first audible in the first trimester at around week 12.Rate this question:
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- 13.
The lungs become capable of respiration in which of the following trimesters?
- A.
First trimester
- B.
Second trimester
- C.
Third trimester
Correct Answer
B. Second trimesterExplanation
The lungs become capable of respiration at weeks 25-27 in the second trimesterRate this question:
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- 14.
Leber hereditary optic neuropathy demonstrates which of the following inheritance patterns?
- A.
Mitochondrial inheritance
- B.
X-linked recessive
- C.
Autosomal dominant
- D.
Autosomal recessive
Correct Answer
A. Mitochondrial inheritanceExplanation
. Leber hereditary optic neuropathy demonstrates a mitochondrial inheritance pattern.Rate this question:
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- 15.
Duchenne muscular dystrophy demonstrates which of the following inheritance patterns?
- A.
Mitochondrial inheritance
- B.
X-linked recessive
- C.
Autosomal dominant
- D.
Autosomal recessive
Correct Answer
B. X-linked recessiveExplanation
Duchenne muscular dystrophy demonstrates an X-linked recessive inheritance patternRate this question:
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- 16.
Huntington disease demonstrates which of the following inheritance patterns?
- A.
Mitochondrial inheritance
- B.
X-linked recessive
- C.
Autosomal dominant
- D.
Autosomal recessive
Correct Answer
C. Autosomal dominantExplanation
Huntington disease demonstrates an autosomal dominant inheritance pattern.Rate this question:
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- 17.
Which of the following is inherited entirely through maternal transmission?
- A.
Huntington disease
- B.
Cystic fibrosis
- C.
Duchenne muscular dystrophy
- D.
Leber hereditary optic neuropathy
Correct Answer
D. Leber hereditary optic neuropathyExplanation
Leber hereditary optic neuropathy involves a mutation in the ND4 gene located on mitochondrial DNA. All mitochondrial DNA is inherited only from the mother because sperm (male) mitochondria do not pass into the ovum at fertilizationRate this question:
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- 18.
Which of the following genetic diseases involves a mutation in a Cl- channel?
- A.
Huntington disease
- B.
Cystic fibrosis
- C.
Duchenne muscular dystrophy
- D.
Leber hereditary optic neuropathy
Correct Answer
B. Cystic fibrosisExplanation
Cystic fibrosis is an autosomal recessive disease that involves a mutation in the CF gene that encodes for a Cl- channel.Rate this question:
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Mar 22, 2023Quiz Edited by
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Mar 26, 2012Quiz Created by
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