downs syndrome is caused by

HESI LPN

HESI Maternal Newborn

1. What causes Down's syndrome?

A. Alcohol abuse by the mother at the time of conception.
B. Sex-linked chromosomal abnormalities.
C. An extra chromosome on the 21st pair.
D. Drug abuse by the mother during pregnancy.

Correct answer: C

Rationale: Down's syndrome, also known as trisomy 21, is caused by the presence of an extra chromosome on the 21st pair. Choice A is incorrect as alcohol abuse is not the cause of Down's syndrome. Choice B is incorrect because Down's syndrome is not related to sex-linked chromosomal abnormalities. Choice D is also incorrect as drug abuse by the mother during pregnancy is not the cause of Down's syndrome.

2. A newborn's head circumference is 12 inches (30.5 cm) and his chest measurement is 13 inches (33 cm). The nurse notes that this infant has no molding, and it was a breech presentation delivered by cesarean section. What action should the nurse take based on this data?

A. No action needs to be taken, it is normal for an infant born by cesarean section to have a small head circumference.
B. Notify the pediatrician immediately. These signs support the possibility of hydrocephalus.
C. Call these findings to the attention of the pediatrician. The head/chest ratio is abnormal.
D. Record the findings on the chart. They are within normal limits.

Correct answer: D

Rationale: Head and chest circumference measurements are within normal limits for a newborn, especially for those delivered by cesarean section, so no immediate action is required beyond documentation.

3. A newborn is 1 hour old with a respiratory rate of 50/min, a heart rate of 130/min, and an axillary temperature of 36.1°C (97°F). Which of the following actions should be taken?

A. Give the newborn a warm bath.
B. Apply a cap to the newborn's head.
C. Reposition the newborn.
D. Obtain an oxygen saturation level.

Correct answer: B

Rationale: Applying a cap to the newborn's head is the correct action in this scenario. Newborns are at risk of heat loss due to their high surface area to volume ratio, and maintaining their body temperature is crucial to prevent hypothermia. Giving a warm bath can further increase heat loss and is not recommended. Repositioning the newborn may not address the primary concern of temperature regulation. While monitoring oxygen saturation is important, addressing thermal regulation takes precedence in this situation.

4. 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.

5. A client in labor requests nonpharmacological pain management. Which of the following nursing actions promotes client comfort?

A. Assisting the client into a squatting position
B. Having the client lie in a supine position
C. Applying fundal pressure during contractions
D. Encouraging the client to void every 6 hours

Correct answer: A

Rationale: Assisting the client into a squatting position promotes comfort during labor. This position can help relieve pain by utilizing gravity, allowing the pelvic outlet to widen, and potentially facilitating the progress of labor. Lying in a supine position (Choice B) can hinder labor progression and increase discomfort. Applying fundal pressure (Choice C) can be inappropriate and may cause harm as it is not routinely recommended during labor. Encouraging the client to void every 6 hours (Choice D) is important for bladder management but does not directly address pain relief during labor.