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HESI Focus on Maternity Exam
1. What is the typical sex chromosome pattern for males?
- A. XX
- B. XYY
- C. XY
- D. XXY
Correct answer: C
Rationale: The correct answer is C: XY. In males, the typical sex chromosome pattern consists of one X chromosome and one Y chromosome. Choice A (XX) is the sex chromosome pattern for females. Choice B (XYY) is a chromosomal disorder where males have an extra Y chromosome. Choice D (XXY) is the sex chromosome pattern associated with Klinefelter syndrome, a condition where males have an extra X chromosome.
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. A newborn nursery protocol includes a prescription for ophthalmic erythromycin 5% ointment to both eyes upon a newborn's admission. What action should the nurse take to ensure adequate installation of the ointment?
- A. Instill a thin ribbon into each lower conjunctival sac
- B. Occlude the inner canthus after retracting the eyelids
- C. Mummy wrap the infant before instilling the ointment
- D. Stabilize the instilling hand on the neonate's head
Correct answer: A
Rationale: To ensure adequate installation of the ophthalmic erythromycin 5% ointment in a newborn, the nurse should instill a thin ribbon into each lower conjunctival sac. This method helps to ensure proper distribution and effectiveness of the medication to prevent neonatal conjunctivitis. Choices B, C, and D are incorrect. Occluding the inner canthus after retracting the eyelids, mummy wrapping the infant, or stabilizing the instilling hand on the neonate's head are not appropriate actions for ensuring the proper installation of the ointment.
4. Do dizygotic (DZ) twins run in families?
- A. Yes
- B. No
- C. Rarely
- D. Never
Correct answer: A
Rationale: Yes, dizygotic (DZ) twins can run in families. This is due to genetic factors that influence hyperovulation, where a woman releases multiple eggs during her menstrual cycle. This genetic predisposition can be passed down through generations, increasing the likelihood of having dizygotic twins. Choices B, C, and D are incorrect because the statement that dizygotic twins run in families is true, as supported by scientific evidence. It is important to note that while the genetic predisposition for dizygotic twins can run in families, it does not guarantee that every generation will have twins, as other factors also play a role in twin pregnancies.
5. Polygenic traits are those that are:
- A. developed during adolescence.
- B. transmitted by the mother.
- C. uncommon in humans.
- D. determined by several pairs of genes.
Correct answer: D
Rationale: Polygenic traits, such as height and skin color, are determined by several pairs of genes working together. These traits are influenced by the combined effects of multiple genes across the genome, rather than being controlled by a single gene pair. Choices A, B, and C are incorrect because polygenic traits are not specifically developed during adolescence, transmitted by the mother, or uncommon in humans. Understanding polygenic traits is essential in genetics as they demonstrate the complexity of genetic inheritance and the influence of multiple genes on a single trait.
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