Nursing Elites

1. The _____ is the inner layer of the embryo from which the lungs and digestive system develop.

• A. neural tube
• B. mesoderm
• C. endoderm
• D. umbilical cord

Correct answer: C

Rationale: The endoderm is the correct answer. It is the innermost layer of the embryo that gives rise to organs such as the lungs, digestive system, liver, and pancreas. The neural tube (Choice A) forms the brain and spinal cord, not the lungs or digestive system. Mesoderm (Choice B) develops into structures like muscles, bones, and circulatory system, not the lungs or digestive system. The umbilical cord (Choice D) serves as a connection between the embryo and the placenta, providing nutrients and oxygen, but it is not the layer from which lungs and digestive system develop.

2. Before meiosis, a sperm cell:

• A. contains 46 chromosomes.
• B. contains two X chromosomes.
• C. is significantly larger than an egg cell.
• D. contains both an X and a Y chromosome.

Correct answer: A

Rationale: Before meiosis, a sperm cell contains 46 chromosomes. This is because sperm cells, like other somatic cells, have a diploid number of chromosomes. During meiosis, the number of chromosomes is halved to 23 to combine with an egg cell during fertilization. Choice B is incorrect because a sperm cell carries either an X or a Y chromosome, not both (Choice D). Choice C is incorrect as sperm cells are generally smaller than egg cells, which is an adaptation that aids in motility and penetration of the egg during fertilization.

3. Females with Turner syndrome:

• A. possess more thymine than cytosine.
• B. are taller than average.
• C. produce little estrogen.
• D. are more likely to give birth to twins.

Correct answer: C

Rationale: Turner syndrome is a chromosomal disorder in females characterized by short stature and underdeveloped ovaries, resulting in low estrogen production. This leads to symptoms such as delayed puberty and infertility. Choice A is incorrect because the chromosomal abnormality in Turner syndrome does not affect the thymine-cytosine ratio. Choice B is incorrect as females with Turner syndrome are typically shorter than average. Choice D is incorrect as Turner syndrome does not increase the likelihood of giving birth to twins.

4. A 25-year-old gravida 3, para 2 client gave birth to a 9-pound, 7-ounce boy 4 hours ago after augmentation of labor with oxytocin (Pitocin). She presses her call light and asks for her nurse right away, stating 'I’m bleeding a lot.' What is the most likely cause of postpartum hemorrhage in this client?

• A. Retained placental fragments.
• B. Unrepaired vaginal lacerations.
• C. Uterine atony.
• D. Puerperal infection.

Correct answer: C

Rationale: Uterine atony is the most likely cause of bleeding 4 hours after delivery, especially after delivering a macrosomic infant and augmenting labor with oxytocin. Uterine atony is characterized by the inability of the uterine muscles to contract effectively after childbirth, leading to excessive bleeding. The other options, such as retained placental fragments (A), unrepaired vaginal lacerations (B), and puerperal infection (D), are less likely causes of postpartum hemorrhage in this scenario. Retained placental fragments can cause bleeding, but this typically presents earlier than 4 hours postpartum. Unrepaired vaginal lacerations would likely be evident sooner and not typically result in significant bleeding. Puerperal infection is not a common cause of immediate postpartum hemorrhage unless there are other signs of infection present.

5. Which field of biology studies heredity?

• A. Etiology.
• B. Ecology.
• C. Genetics.
• D. Eugenics.

Correct answer: C

Rationale: Genetics is the branch of biology that focuses on the study of heredity and variation in organisms. Etiology (choice A) deals with the causes of diseases, not heredity. Ecology (choice B) is concerned with the relationships between organisms and their environment, not specifically heredity. Eugenics (choice D) is a controversial field that involves improving the genetic quality of the human population through selective breeding, which is different from the study of heredity itself.

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