Men who take large doses of testosterone-like androgenic steroids for long periods are sterile in the reproductive sense of the word. What is the explanation for this finding?

Correct Answer: C

Rationale: The correct answer is C because high levels of androgen compounds inhibit the secretion of gonadotropin-releasing hormone (GnRH) by the hypothalamus. GnRH is responsible for stimulating the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) by the anterior pituitary gland. LH and FSH are crucial for proper testicular function, including sperm production. When the secretion of GnRH is inhibited by high levels of androgens, it leads to a decrease in LH and FSH levels, ultimately disrupting the normal feedback loop of the hypothalamic-pituitary-gonadal axis. This disruption results in impaired sperm production and fertility. Choice A is incorrect because overstimulation of inhibin formation does not directly lead to sterility. Choice B is incorrect because overstimulation of sperm cell production would not result in the formation of defective sperm cells leading to sterility. Choice D is incorrect because hypert

Correct Answer: D

Rationale: The correct answer is D: acrosome. The acrosome is a specialized organelle in the sperm head that contains enzymes necessary for penetrating the egg during fertilization. It releases these enzymes to help the sperm penetrate the egg's protective outer layer. The flagellum (choice A) is the tail of the sperm that provides motility. The midpiece (choice B) contains mitochondria for energy production. Spermatid (choice C) is an immature sperm cell formed during spermatogenesis.

Correct Answer: B

Rationale: The correct answer is B: Epididymis. The epididymis is where maturing sperm gain increased motility and their ability to swim due to the presence of specific proteins and enzymes that facilitate this process. Sperm leave the seminiferous tubules in an immature state and undergo maturation in the epididymis through interactions with these proteins. The ductus deferens and ejaculatory duct are not involved in the maturation process of sperm and do not contribute to their motility. The seminiferous tubules are responsible for sperm production but not for the maturation of sperm motility.

Correct Answer: B

Rationale: The correct answer is B: Onset of menopause. Puberty is the period of sexual maturation and development, typically occurring in adolescence. Menopause, on the other hand, is the cessation of menstruation and fertility, usually happening in women in their late 40s or early 50s. During puberty in females, there is an increase in fat deposits beneath the skin, widening and lightening of the pelvis to prepare for childbirth, and development of the breasts as part of secondary sexual characteristics. Menopause does not occur during puberty; it is a separate phase in a woman's reproductive life cycle. Therefore, B is the correct answer.

Correct Answer: A

Rationale: The correct answer is A because the corpus luteum secretes progesterone, not FSH. Oogenesis produces ova/ovum, not FSH, LH, or prolactin. FSH and LH are hormones produced by the pituitary gland to regulate the menstrual cycle, not by the corpus luteum or involved in ova production. Prolactin is a hormone involved in milk production, not in oogenesis or corpus luteum function. Therefore, A is correct as it correctly identifies the function of the corpus luteum and the product of oogenesis.