The layer of the uterine wall that is shed during menstruation is the

Correct Answer: A

Rationale: The correct answer is A: endometrium. During menstruation, the endometrium, the inner lining of the uterus, is shed. This layer thickens throughout the menstrual cycle in preparation for possible implantation of a fertilized egg. If fertilization does not occur, the endometrium is shed during menstruation. B: myometrium is incorrect because it is the middle layer of the uterine wall consisting of smooth muscle tissue, responsible for contracting during labor. C: epimetrium is incorrect as it is not a recognized term in anatomy. The outer layer of the uterus is called the perimetrium. D: none of the above is incorrect as the endometrium is the specific layer of the uterine wall that is shed during menstruation.

Correct Answer: A

Rationale: The correct answer is A: Fetal hypoxia during the birth process. Fetal hypoxia, which is a lack of oxygen to the fetus during birth, can lead to delayed breathing in newborn infants. This lack of oxygen can result from various factors such as umbilical cord compression or placental insufficiency. Maternal hypoxia (choice B) and hypercapnia (choices C and D) may affect the fetus indirectly but are not direct causes of delayed breathing in newborns. Therefore, the correct choice is A, as it directly addresses the specific cause of delayed breathing in newborn infants.

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: A

Rationale: Step 1: Testosterone plays a crucial role in maintaining bone density. Step 2: Estrogen helps regulate bone turnover and calcium balance. Step 3: Women experience a significant drop in estrogen levels after menopause. Step 4: Decreased estrogen production leads to increased bone resorption. Step 5: Men, on the other hand, continue to produce testosterone throughout their lifetime, which helps maintain bone density. Summary: A is correct because men maintain testosterone production, while women cease estrogen production after menopause, leading to a higher risk of osteoporosis in elderly women. B, C, and D are incorrect as they do not address the hormonal changes that contribute to osteoporosis gender disparity.

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.