How many autosomes does a human primary spermatocyte have?
- A. 34
- B. 44
- C. 54
- D. 33
Correct Answer: B
Rationale: The correct answer is B (44 autosomes) because a human primary spermatocyte is a diploid cell containing a total of 44 autosomes. This is because humans have 22 pairs of autosomes in their somatic cells. During meiosis I, the primary spermatocyte undergoes replication and recombination, resulting in 22 pairs of autosomes (44 autosomes) that will be divided into two haploid secondary spermatocytes. Choices A, C, and D are incorrect because they do not reflect the correct number of autosomes present in a human primary spermatocyte.
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How many seminiferous tubules are found in each lobule?
- A. 1-3
- B. 50-100
- C. 200-300
- D. 500 or more
Correct Answer: B
Rationale: The correct answer is B (50-100) because each lobule in the testis contains multiple seminiferous tubules where sperm production occurs. The average number of seminiferous tubules per lobule ranges from 50 to 100. This is supported by anatomical studies and research on testicular structure.
Explanation:
A: 1-3 - This is too low as each lobule contains more seminiferous tubules for efficient sperm production.
C: 200-300 - This is too high as it overestimates the number of seminiferous tubules per lobule.
D: 500 or more - This is excessive and not accurate based on scientific findings.
In summary, choice B is correct because it accurately reflects the typical range of seminiferous tubules per lobule, while the other choices either underestimate or overestimate this number.
Sexual feelings are normal and necessary
- A. for reproduction to occur
- B. for the heart and lungs to function properly
- C. for an ovum to be released from a female’s ovary each month
- D. for teens to become adults
Correct Answer: A
Rationale: The correct answer is A because sexual feelings are indeed necessary for reproduction to occur. Sexual arousal and desire play a vital role in initiating the process of conception and ensuring the continuation of the human species. Without sexual feelings, procreation would not be possible.
Explanation for why the other choices are incorrect:
B: Sexual feelings are not necessary for the heart and lungs to function properly. These bodily functions are regulated by the autonomic nervous system, not by sexual arousal.
C: While sexual feelings can influence the release of an ovum during ovulation, they are not the sole factor. Ovulation can occur without sexual arousal.
D: Sexual feelings are not a requirement for teenagers to become adults. Puberty and the physical and emotional changes that come with it mark the transition from adolescence to adulthood, not sexual feelings.
A cell called the ______ is a fertilized cell with 46 chromosomes.
- A. spermatozoon
- B. polar body
- C. ovum
- D. zygote
Correct Answer: D
Rationale: The correct answer is D: zygote. A zygote is formed when a sperm cell fertilizes an egg cell, resulting in a single cell with a full set of 46 chromosomes. This process is called fertilization and marks the beginning of a new individual. The other choices (A: spermatozoon, B: polar body, C: ovum) are not correct because a spermatozoon is a mature sperm cell with 23 chromosomes, a polar body is a byproduct of meiosis in the female reproductive system and has only 23 chromosomes, and an ovum is an unfertilized egg cell also containing 23 chromosomes.
Advanced breast cancer often metastasizes to the bone. If this occurs, a prudent nursing measure would be to
- A. encourage a diet high in calcium
- B. caution the patient against falling, reaching, twisting, or lifting heavy objects
- C. encourage the patient to abstain from sexual intercourse
- D. caution the patient about using any pain medication
Correct Answer: B
Rationale: Preventing falls and injuries is crucial in patients with bone metastasis due to increased fracture risk.
Following ejaculation, arterial blood flow into the corpora cavernosa decreases back to the normal resting level resulting in the flaccid state. What is the best explanation for this decrease in blood flow?
- A. Systemic arterial pressure decreases due to absence of sexual stimulation
- B. The level of sympathetic stimulation to the arterioles supplying the corpora cavernosa decreases
- C. Resistance of the arterioles supplying the corpora cavernosa increases
- D. Formation of nitric oxide in the endothelial cells of the arterioles supplying the corpora cavernosa is stimulated by the increase in parasympathetic nervous system activity
Correct Answer: C
Rationale: The correct answer is C because the resistance of the arterioles supplying the corpora cavernosa increases. This occurs due to the contraction of smooth muscle in the arterioles stimulated by sympathetic nervous system activity post-ejaculation. This constriction of arterioles reduces blood flow into the corpora cavernosa, leading to the flaccid state.
Choice A is incorrect because systemic arterial pressure does not decrease significantly post-ejaculation. Choice B is incorrect as decreased sympathetic stimulation would actually lead to vasodilation, not vasoconstriction. Choice D is incorrect because the release of nitric oxide by the parasympathetic nervous system would lead to vasodilation, not vasoconstriction.