What is the total number of chromosomes contained in a mature sperm or ovum?

Correct Answer: B

Rationale: In reproductive biology and genetics, understanding the number of chromosomes in sperm and ova is crucial. The correct answer is B) 23 chromosomes. This is because sperm and ova are gametes, which are haploid cells containing half the number of chromosomes found in somatic cells (diploid cells). When a sperm fertilizes an ovum during conception, the resulting zygote will have the full complement of 46 chromosomes. Option A) 22 chromosomes is incorrect because having only 22 chromosomes would not result in a complete set necessary for normal human development. Option C) 44 chromosomes is incorrect as it represents a diploid number, which is found in somatic cells, not in gametes. Option D) 46 chromosomes is incorrect because that is the total number of chromosomes found in a somatic cell, not in a mature sperm or ovum. Understanding the chromosomal composition of gametes is essential in comprehending concepts like genetic inheritance, chromosomal disorders, and embryonic development. This knowledge is fundamental in fields such as genetics, obstetrics, and reproductive medicine. It forms the basis for discussions on genetic counseling, infertility treatments, and prenatal screening. By grasping this concept, healthcare professionals can better educate and support patients in making informed decisions regarding their reproductive health.

Correct Answer: B

Rationale: In the context of fetal development, the correct answer is B) 20 weeks for the fetal age of viability. Viability refers to the point in pregnancy at which a fetus is considered capable of surviving outside the womb with medical support. At around 20 weeks gestation, the fetus has reached a stage where it may have a chance of survival if born prematurely. This milestone is significant in obstetrics and neonatology as it marks a critical point in the continuum of fetal development. Option A) 14 weeks is too early for fetal viability as at this stage, the fetus is still in the first trimester and not yet developed enough to survive outside the womb. Option C) 25 weeks and Option D) 30 weeks are both beyond the generally accepted age of viability (around 24 weeks) but they are not the standard point at which viability is typically considered. Educationally, understanding fetal viability is crucial for expectant parents as it highlights the importance of prenatal care, monitoring, and the potential outcomes in case of premature birth. This knowledge empowers parents to make informed decisions and be prepared for any possible scenarios during pregnancy and childbirth.

Correct Answer: A

Rationale: In embryology, understanding the primary germ layers is crucial as they give rise to all the tissues and organs in the human body. The correct answer is A) Ectoderm. The ectoderm is one of the primary germ layers that develops into the nervous system, skin, hair, and nails. This layer is responsible for forming the outermost layer of the embryo. Option B) Endoderm is incorrect because it gives rise to the innermost layer of the digestive and respiratory tracts, as well as some internal organs like the liver and pancreas. Option C) Mesoderm is incorrect because it forms the middle layer of the embryo and develops into structures such as muscles, bones, blood, and the circulatory system. Option D) Plastoderm is not a correct germ layer and is a distractor in this question. In an educational context, teaching high school students about the primary germ layers helps them understand the complexity of human development and how different tissues and organs originate from these fundamental layers. This knowledge is essential for students interested in fields like medicine, biology, or embryology. Understanding the germ layers lays the foundation for comprehending the intricate process of fetal development and organogenesis.

Correct Answer: C

Rationale: Primitive spinal cord and brain appear at 3 weeks. Neural tube closes at 4 weeks. Skull and jaw ossify at 6 weeks. Spleen stops forming blood cells and bone marrow takes over at 29 weeks. Subcutaneous fat is present at 36 weeks. This sequence reflects the chronological progression of key developmental milestones.

Correct Answer: B

Rationale: In the context of maternal fetal monitoring, it is crucial for nurses to understand their role in diagnostic testing. The correct answer is B) Information about the tests. Nurses play a pivotal role in providing accurate and comprehensive information to the expectant couple regarding the diagnostic tests being conducted. Providing advice to the couple (Option A) may not be within the nurse's scope of practice, as nurses typically focus on providing evidence-based information rather than personal opinions. Reassuring about fetal safety (Option C) is important, but the primary role of the nurse in diagnostic testing is to provide factual information to help the couple make informed decisions. Assistance with decision-making (Option D) is also important, but this typically follows after the nurse has provided the necessary information about the tests. By choosing option B, the nurse empowers the couple to understand the purpose, procedure, and potential outcomes of the diagnostic tests, enabling them to make informed decisions regarding their care and the well-being of their unborn child. In an educational context, understanding the nurse's role in diagnostic testing not only ensures safe and effective care for the mother and baby but also emphasizes the importance of patient education and autonomy in the decision-making process during pregnancy. Nurses serve as advocates for their patients by providing accurate information, promoting shared decision-making, and supporting expectant parents through the various stages of maternal fetal monitoring.