Testosterone produces negative feedback to:

Correct Answer: D

Rationale: Step-by-step rationale: 1. Testosterone inhibits the release of luteinizing hormone (LH) through negative feedback. 2. LH is produced by the anterior pituitary. 3. Therefore, testosterone exerts negative feedback on the anterior pituitary to turn off LH secretion. 4. This maintains hormonal balance in the body. Summary of other choices: A. Incorrect because testosterone primarily affects LH secretion, not follicle stimulating hormone (FSH). B. Incorrect as it inaccurately suggests that testosterone turns off both LH and FSH secretion. C. Incorrect because Sertoli cells are involved in spermatogenesis, not LH regulation.

Correct Answer: B

Rationale: The correct answer is B: Cervix. The cervix is the narrow passage that connects the uterus to the vagina. It acts as a barrier between the uterus and the outside environment. The other choices are incorrect because: A: Vagina is the birth canal and does not directly connect the ovary to the uterus. C: Fallopian tube connects the ovary to the uterus but does not directly attach to it. D: Perineorrhaphy is a surgical procedure to repair the perineum and is not related to connecting the ovary to the uterus.

Correct Answer: C

Rationale: The correct answer is C: labia. The labia minora are two inner folds that cover and protect the vaginal opening. This is because the labia minora are part of the external female genitalia and specifically designed to provide protection to the vaginal opening. A: Uterus - Incorrect. The uterus is a separate organ and is not involved in covering or protecting the vaginal opening. B: Fallopian tubes - Incorrect. The fallopian tubes are part of the reproductive system but are not located near the vaginal opening or involved in its protection. D: Vagina - Incorrect. While the vagina is connected to the vaginal opening, it is not the structure that directly covers and protects it.

Correct Answer: C

Rationale: The correct answer is C because spermatogenesis occurs within the convoluted seminiferous tubules of the testes. This is where sperm cells are produced through a series of cell divisions and maturation processes. Choice A is incorrect as spermatogenesis does not occur at the level of testicular interstitial cells, which are responsible for hormone production. Choice B is also incorrect as Leydig cells are responsible for testosterone production, not sperm production. Choice D is incorrect as spermatogenesis actually begins during puberty, typically around the age of 12-13, not specifically at the age of 14.

Correct Answer: A

Rationale: The correct answer is A because the ejaculatory duct is formed by the joining of the deferent duct (vas deferens) with the seminal vesicle duct. This is important for transporting sperm and seminal fluid towards the urethra for ejaculation. Choice B is incorrect because the ejaculatory duct does not open directly into the urethra; rather, it joins with the urethra. Choice C is incorrect as the ejaculatory duct is not extratesticular; it is located within the prostate gland. Choice D is incorrect as the ejaculatory duct is not located within the testicle; it is formed outside the testicle by the union of other structures.