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HESI Focus on Maternity Exam
1. Which synthetic hormone is used to prevent miscarriages and can cause masculinization of the fetus?
- A. Testosterone
- B. Estrogen
- C. Progestin
- D. Oxytocin
Correct answer: C
Rationale: Progestin is the synthetic hormone used to prevent miscarriages. While it is beneficial in maintaining pregnancy, in some cases, it can lead to masculinization of the fetus. Testosterone (Choice A) and estrogen (Choice B) are not typically used to prevent miscarriages and do not cause masculinization of the fetus in this context. Oxytocin (Choice D) is a hormone involved in labor and breastfeeding, but it is not used to prevent miscarriages nor does it cause masculinization of the fetus.
2. Which of the following most accurately describes the function of genes?
- A. They regulate the development of traits.
- B. They prevent foreign particles from entering the body.
- C. They work together with lutein to influence development.
- D. They transfer oxygen from the bloodstream to other parts of the body.
Correct answer: A
Rationale: The correct answer is A: 'They regulate the development of traits.' Genes play a crucial role in regulating the development of traits by encoding proteins that control various bodily functions and characteristics. This process involves gene expression and the production of proteins that ultimately determine an individual's traits. Choice B is incorrect because genes do not have a direct role in preventing foreign particles from entering the body; this function is primarily carried out by the immune system. Choice C is incorrect as genes do not specifically work with lutein to influence development; genes operate independently to regulate trait expression. Choice D is incorrect as genes are not responsible for transferring oxygen in the bloodstream; this function is carried out by red blood cells and hemoglobin.
3. What is the primary role of meiosis in the production of sperm and ova?
- A. To reduce the chromosome number by half
- B. To increase the chromosome number
- C. To create identical copies of chromosomes
- D. To repair damaged chromosomes
Correct answer: A
Rationale: The correct answer is A. Meiosis is a type of cell division that reduces the chromosome number by half, resulting in the formation of sperm and ova. Choice B is incorrect because meiosis does not increase the chromosome number. Choice C is incorrect because meiosis creates genetically diverse gametes, not identical copies of chromosomes. Choice D is incorrect because meiosis does not primarily function to repair damaged chromosomes.
4. According to a survey by Adhikari and Liu in the year 2013, at birth, women have:
- A. close to 100,000 ova.
- B. around 300,000 to 400,000 ova.
- C. around 100 to 200 ova.
- D. only 500 ova.
Correct answer: B
Rationale: Women are born with approximately 300,000 to 400,000 ova, which gradually decrease in number as they age. Choice A ('close to 100,000 ova.') is incorrect as the actual number is much higher. Choice C ('around 100 to 200 ova.') is incorrect as it underestimates the quantity significantly. Choice D ('only 500 ova.') is incorrect as it greatly underestimates the number of ova present at birth.
5. What is the central layer of the embryo from which the bones and muscles develop?
- A. neural tube
- B. mesoderm
- C. ectoderm
- D. umbilical cord
Correct answer: B
Rationale: The correct answer is mesoderm. The mesoderm is the middle layer of the embryo that gives rise to the bones, muscles, and other connective tissues. The neural tube (choice A) develops into the nervous system, not bones and muscles. The ectoderm (choice C) forms the skin and nervous system, not bones and muscles. The umbilical cord (choice D) is a structure that connects the developing fetus to the placenta; it is not a layer of the embryo that gives rise to bones and muscles.
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