Nokea
The nurse is explaining fetal circulation to a group of nursing students. Which information should be included in the teaching session? (Select all that apply.)
- A. After birth the ductus venosus remains open, but the other shunts close
- B. The foramen ovale shunts blood from the right atrium to the left atrium.
- C. The ductus venosus shunts blood from the liver to the inferior vena cava
- D. The ductus venosus shunts blood from the liver to the inferior vena cav
Correct Answer: C
Rationale: The correct answer is C: The ductus venosus shunts blood from the liver to the inferior vena cava. During fetal circulation, the ductus venosus allows oxygenated blood from the placenta to bypass the liver and flow directly into the inferior vena cava. This is important for fetal circulation as the liver is not fully functional in the fetus. After birth, the ductus venosus closes as the liver becomes fully operational.
Rationale for incorrect choices:
A: After birth, the ductus venosus closes, not remains open.
B: The foramen ovale shunts blood from the right atrium to the left atrium, not related to the ductus venosus.
D: This choice is a repetition of the correct information but incorrectly states the destination of the shunted blood.
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The nurse caring for the laboring woman should know that meconium is produced by:
- A. Fetal intestines.
- B. Fetal kidneys.
- C. Amniotic fluid.
- D. The placenta.
Correct Answer: A
Rationale: As the fetus nears term, fetal waste products accumulate in the intestines as dark green-to-black, tarry meconium.
The time period immediately following fertilization results in which circumstance?
- A. Formation of a zygote that contains the haploid number of chromosomes
- B. Formation of an embryo that contains the haploid number of chromosomes
- C. Formation of a zygote that contains the diploid number of chromosomes
- D. Formation of a 16-cell morula
Correct Answer: C
Rationale: The correct answer is C: Formation of a zygote that contains the diploid number of chromosomes. After fertilization, the sperm and egg combine to form a zygote with a complete set of chromosomes (diploid). This is crucial for genetic diversity and proper development.
Choice A is incorrect because a zygote is diploid, not haploid. Choice B is incorrect as an embryo is formed later in development and contains diploid chromosomes. Choice D is incorrect because a morula is a stage where the zygote undergoes several rounds of cell division, but it does not yet contain a full diploid set of chromosomes.
What hormone is secreted by the corpus luteum after ovulation?
- A. prolactin
- B. progesterone
- C. luteinizing hormone
- D. follicle-stimulating hormone
Correct Answer: B
Rationale: The correct answer is B: progesterone. After ovulation, the ruptured follicle transforms into the corpus luteum, which secretes progesterone. Progesterone plays a crucial role in preparing the uterus for implantation and maintaining pregnancy. Prolactin (A) is a hormone mainly involved in milk production. Luteinizing hormone (C) triggers ovulation and the release of the egg from the ovary. Follicle-stimulating hormone (D) is responsible for stimulating the growth of ovarian follicles. The key is understanding the physiological processes post-ovulation and the role of progesterone in these processes.
The nurse is explaining the process of cell division during the preembryonic period to a group of nursing students. Which statement best describes the characteristics of the morula?
- A. Fertilized ovum before mitosis begins
- B. Double layer of cells that becomes the placenta
- C. Flattened, disk-shaped layer of cells within a fluid-filled sphere
- D. Solid ball composed of the first cells formed after fertilization
Correct Answer: D
Rationale: The correct answer is D because a morula is a solid ball composed of the first cells formed after fertilization. During the preembryonic period, the zygote undergoes several rounds of cell division to form a morula, which is a compact cluster of cells. A: is incorrect as a fertilized ovum is a zygote, not a morula. B: is incorrect as the double layer of cells that becomes the placenta is the bilaminar germ disc, not the morula. C: is incorrect as a flattened, disk-shaped layer of cells within a fluid-filled sphere describes the blastocyst, not the morula. Thus, the characteristics of a morula being a solid ball composed of the first cells formed after fertilization make option D the correct choice.
Conjoined twins are formed at which point of gestation?
- A. Immediately after fertilization
- B. At the time of implantation
- C. At about 13 to 15 days after conception
- D. In the blastocyst stage
Correct Answer: C
Rationale: Conjoined twins are formed at about 13 to 15 days after conception when the embryonic disc undergoes incomplete splitting. At this stage, the cells have already differentiated into different layers, making separation challenging. Immediately after fertilization (choice A) is too early for conjoined twins to form. At the time of implantation (choice B) is when the blastocyst implants into the uterine wall, but conjoined twins are not formed at this point. In the blastocyst stage (choice D), the cells are still in the process of organizing and have not yet differentiated into distinct layers. Therefore, choice C is the correct answer as it aligns with the timing of conjoined twin formation during embryonic development.