Sem1mini2 - Placental Development
- 1.
The absence of a ventral double-fold of coelomic membrane connecting the heart to the ventral body wall (a ventral mesocardium) is a result of
- A.
Degeneration of this mesentery
- B.
Formation of the pericardiopleural canals
- C.
Formation of the pleuroperitoneal canals
- D.
Absence of a ventral mesentery on the ventral body wall below the ligamentum teres
- E.
A bilateral connection of the early intraembryonic coelom rostral to the developing heart
Correct Answer
E. A bilateral connection of the early intraembryonic coelom rostral to the developing heartExplanation
The absence of a ventral double-fold of coelomic membrane connecting the heart to the ventral body wall (a ventral mesocardium) is a result of a bilateral connection of the early intraembryonic coelom rostral to the developing heart.Rate this question:
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- 2.
After the twentieth week of gestation, a thinned vasculosyncytial placental membrane is formed consisting of the following three layers:
- A.
Syncytiotrophoblast – cytotrophoblast – fetal capillary endothelium
- B.
Maternal capillary endothelium - syncytiotrophoblast – fetal capillary epithelium
- C.
Syncytiotrophoblast – connective tissue of the villus – fetal capillary endothelium
- D.
Connective tissue of the villus – syncytiotrophoblast - maternal capillary endothelium
- E.
Maternal capillary endothelium – syncytiotrophoblast – cytotrophoblas
Correct Answer
C. Syncytiotrophoblast – connective tissue of the villus – fetal capillary endotheliumExplanation
After the twentieth week of gestation, the placental membrane is thinned and consists of three layers: syncytiotrophoblast, connective tissue of the villus, and fetal capillary endothelium. This arrangement allows for efficient exchange of nutrients and waste products between the maternal and fetal circulations. The syncytiotrophoblast layer is responsible for nutrient transfer and hormone production, while the connective tissue of the villus provides structural support. The fetal capillary endothelium allows for the exchange of gases and other substances between the maternal and fetal blood.Rate this question:
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- 3.
A 37-year-old women in the fourth month of pregnancy is diagnosed with aggressive ovarian cancer. Her physician advises immediate surgery to remove her ovaries. The woman wants to deliver her baby and has read on the internet that she will have an abortion if her ovaries are removed. She comes to your office for a second opinion. You recommend that
- A.
She postpone the surgery until after the birth of her child
- B.
She postpone the surgery until the third trimester of her pregnancy
- C.
She immediately have the surgery with post-operative progesterone supplements
- D.
She immediately have the surgery with estrogen supplements
- E.
She immediately have the surgery with no hormonal steroid supplements
Correct Answer
E. She immediately have the surgery with no hormonal steroid supplements -
- 4.
Ectopia cordis or Pentalogy of Cantrell is a congenital malformation of the anterior body wall that includes a defect of the lower sternum, a deficient anterior diaphragm, and a heart that lies outside the chest. This condition is primarily a defect in what embryological process?
- A.
Formation of the intraembryonic coelom
- B.
Lateral folding
- C.
Formation of the intermediate mesoderm
- D.
Longitudinal folding
- E.
Formation of the head fold
Correct Answer
B. Lateral foldingExplanation
Lateral folding is the correct answer because ectopia cordis or Pentalogy of Cantrell is a congenital malformation of the anterior body wall, which is formed during the process of lateral folding in embryonic development. Lateral folding involves the folding of the embryo's sides towards the midline, resulting in the formation of the body wall and the closure of the ventral body wall. In the case of ectopia cordis, the failure of proper lateral folding leads to the heart being positioned outside the chest cavity.Rate this question:
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- 5.
Through which blood vessel does the most oxygenated blood flow to supply the fetus?
- A.
Umbilical artery
- B.
Pulmonary artery
- C.
Aorta
- D.
Femoral artery
- E.
Internal carotid artery
Correct Answer
C. AortaExplanation
The most oxygenated blood flows to supply the fetus through the aorta. The aorta is the main artery that carries oxygen-rich blood from the heart to the rest of the body, including the placenta, where the exchange of oxygen and nutrients takes place between the mother and the fetus. From the placenta, the oxygenated blood is then transported to the fetus through the umbilical vein. Therefore, the aorta is the correct answer as it carries the oxygenated blood to nourish the developing fetus.Rate this question:
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- 6.
During Stage 3 of labor, the placenta separates at which layer from the uterus?
- A.
Spongy layer of the decidua basalis
- B.
At the chorionic plate
- C.
Between the chorion and the amnion
- D.
Between the smooth chorion (chorion leave) and the decidua parietalis
- E.
At the umbilical cord
Correct Answer
A. Spongy layer of the decidua basalisExplanation
During Stage 3 of labor, the placenta separates at the spongy layer of the decidua basalis. This layer is located in the uterus and is responsible for anchoring the placenta to the uterine wall. As the placenta detaches, the spongy layer of the decidua basalis is shed, allowing the placenta to be expelled from the uterus. This separation is a natural part of the third stage of labor and is necessary for the completion of the birthing process.Rate this question:
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- 7.
Which hormone is first produced by the syncytiotrophoblast cells of the early placenta to maintain the viability of the corpus luteum?
- A.
Progesterone
- B.
Relaxin
- C.
Human chorionic gonadotropin
- D.
Ectoderm
- E.
Adrenocorticotropin hormone
Correct Answer
C. Human chorionic gonadotropinExplanation
Human chorionic gonadotropin (hCG) is the hormone first produced by the syncytiotrophoblast cells of the early placenta to maintain the viability of the corpus luteum. This hormone plays a crucial role in early pregnancy by stimulating the corpus luteum to continue producing progesterone, which is essential for maintaining the uterine lining and supporting the pregnancy. hCG levels can be detected in the blood or urine to confirm pregnancy, as its production begins shortly after implantation of the fertilized egg in the uterus.Rate this question:
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- 8.
During the final stages of fetal development (5 months to term) the placental barrier is composed of
- A.
Syncytiotrophoblast and endothelial of fetal capillaries
- B.
Cytotrophoblast and endothelial of fetal capillaries
- C.
Syncytiotrbphoblast, cytotrophoblast, mesenchyme and endothelial of fetal capillaries
- D.
Decidua basalis, syncytiotrophchlast and cytotrophoblast
- E.
Decidua parietalis and chorionic frondosum
Correct Answer
A. Syncytiotrophoblast and endothelial of fetal capillariesExplanation
During the final stages of fetal development, the placental barrier is composed of syncytiotrophoblast and endothelial cells of fetal capillaries. The syncytiotrophoblast is responsible for nutrient and gas exchange between the mother and the fetus, while the endothelial cells of fetal capillaries help in the transport of oxygen and nutrients from the placenta to the fetus. This combination of syncytiotrophoblast and endothelial cells ensures proper exchange of substances and supports the growth and development of the fetus.Rate this question:
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- 9.
Which one of the following substances crosses the placental barrier?
- A.
IgA
- B.
Hormones from the pituitary gland
- C.
Maternal cholesterol
- D.
IgG
- E.
Maternal phospholipids
Correct Answer
D. IgGExplanation
IgG is the correct answer because it is the only immunoglobulin that can cross the placental barrier. This allows for passive immunity to be transferred from the mother to the fetus, providing protection against certain infections. IgA, hormones from the pituitary gland, maternal cholesterol, and maternal phospholipids do not cross the placental barrier.Rate this question:
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- 10.
Which of the following structures gives rise to the umbilical arteries and vein?
- A.
The allantois
- B.
The yolk sac
- C.
Chorion
- D.
The chorion frondosum
- E.
Amnion
Correct Answer
A. The allantoisExplanation
The allantois is a structure that develops during embryogenesis and is responsible for the formation of the umbilical arteries and vein. It is an outpouching of the hindgut and is involved in the exchange of gases and waste products between the embryo and the mother. The umbilical arteries carry deoxygenated blood from the fetus to the placenta, while the umbilical vein carries oxygenated blood from the placenta to the fetus.Rate this question:
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- 11.
Most drugs taken during early pregnancy are transported across the placental barrier primarily by:
- A.
Phagocytosis
- B.
Simple diffusion
- C.
Facilitated diffusion
- D.
Active transport
- E.
Pinocytosis
Correct Answer
B. Simple diffusionExplanation
During early pregnancy, most drugs are transported across the placental barrier primarily by simple diffusion. This is because simple diffusion is a passive process that allows molecules to move from an area of higher concentration to an area of lower concentration. The placental barrier is a selectively permeable membrane that allows small molecules, such as drugs, to pass through easily. Since simple diffusion does not require energy or specific carrier proteins, it is the most common method of drug transport across the placenta.Rate this question:
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- 12.
Which of the following substances DOES NOT cross the placental barrier?
- A.
Cortisol – a steroidal hormone
- B.
Triglycerides
- C.
Amino acids
- D.
Glucose
- E.
IgG
Correct Answer
B. TriglyceridesExplanation
Triglycerides are too large and insoluble in water to cross the placental barrier. The placental barrier allows for the exchange of certain substances between the mother and fetus, but it is selective in what it allows to pass through. Cortisol, amino acids, glucose, and IgG can all cross the placental barrier, but triglycerides cannot.Rate this question:
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- 13.
Which of the following cell types is involved in the production of placental estrogen?
- A.
Decidua basalis
- B.
Cytotrophoblast cells
- C.
Yolk sac cells
- D.
Extraembryonic somatic mesoderm
- E.
Syncytiotrophoblast
Correct Answer
E. SyncytiotrophoblastExplanation
Syncytiotrophoblast cells are involved in the production of placental estrogen. These cells are a specialized layer of cells that form the outermost layer of the placenta. They play a crucial role in hormone production during pregnancy, including the production of estrogen. Estrogen is important for maintaining pregnancy, promoting fetal development, and preparing the mother's body for childbirth. Therefore, the correct answer is Syncytiotrophoblast.Rate this question:
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Mar 21, 2023Quiz Edited by
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Dec 07, 2011Quiz Created by
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