A baby is born with a penis, a scrotum with no testes, no vagina, and XX chromosomes. This condition is referred to as hermaphroditism. Which of the following could cause this abnormality?

Correct Answer: D

Rationale: The correct answer is D: Abnormally high levels of testosterone in the maternal blood. This can cause virilization of the female fetus, leading to the development of male external genitalia. Testosterone exposure during fetal development can result in the formation of a penis and scrotum without testes in a genetic female (XX). Rationale: 1. Testosterone is responsible for the development of male external genitalia. 2. XX chromosomes indicate a genetic female. 3. Lack of testes indicates incomplete masculinization. 4. High levels of testosterone can override the default female development pattern. Other choices are incorrect because: A: Human chorionic gonadotropin does not directly affect fetal genital development. B: Estrogen is not responsible for male genital development. C: Luteinizing hormone does not directly influence the development of external genitalia in the fetus.

Correct Answer: B

Rationale: The correct answer is B, after ovulation in a female. After ovulation, the ruptured follicle transforms into a corpus luteum, which secretes progesterone to support the uterine lining. Prior to ovulation (choice A) there is a mature follicle, not a corpus luteum. Choice C is incorrect as the corpus luteum is a structure in the female reproductive system, not present in semen. Choice D is incorrect as the corpus luteum persists for about 14 days after ovulation, not just on the day of ovulation.

Correct Answer: C

Rationale: The correct answer is C: Head. The head of the sperm contains the nucleus, which houses the DNA. The nucleus carries the genetic information required for fertilization. The midpiece contains mitochondria for energy production, the flagellum provides motility, and the tail is a part of the flagellum. Therefore, the head is the only part of the sperm that houses the nucleus and DNA, making it the correct answer.

Correct Answer: C

Rationale: The correct answer is C: Secondary oocyte. After meiosis I, the primary oocyte forms a secondary oocyte. The secondary oocyte is the cell that can be fertilized by a sperm to form a zygote. Polar bodies are products of oogenesis that do not participate in fertilization. Oogonium is a primordial germ cell in the ovary that undergoes mitosis to form primary oocytes. Therefore, the secondary oocyte is the only viable option for fertilization among the choices provided.

Correct Answer: C

Rationale: The correct answer is C: interstitial cell. Bladder infections are commonly referred to as cystitis, which is the inflammation of the bladder. Interstitial cells are found in the bladder wall and play a role in bladder function. Choice A, seminiferous tubule, is incorrect because it is a structure in the testes involved in sperm production. Choice B, nephritis, refers to inflammation of the kidneys, not the bladder. Choice D, diverticulitis, is inflammation of the diverticula in the colon, not related to bladder infections. Therefore, the most appropriate term for bladder infections is interstitial cell.