What is the main function of the Leydig cells in the male reproductive system?

Correct Answer: B

Rationale: The correct answer is B: Leydig cells secrete testosterone. These specialized cells are located in the testes and are responsible for producing and releasing testosterone, the primary male sex hormone. Testosterone plays a crucial role in the development of male reproductive organs, sperm production, sex drive, and secondary sexual characteristics. Choice A is incorrect because sperm production is primarily carried out by the Sertoli cells. Choice C is incorrect as Leydig cells do not store sperm. Choice D is incorrect as sperm transport is mainly facilitated by the vas deferens and other structures in the male reproductive system.

Correct Answer: D

Rationale: The correct answer is D: All of the above. 1. FSH (Follicle-Stimulating Hormone) stimulates the production of sperms in the testes. 2. LH (Luteinizing Hormone) stimulates Leydig cells in the testes to produce testosterone, which is essential for sperm production. 3. Testosterone is crucial for the maintenance of spermatogenesis. Therefore, all three hormones (FSH, LH, Testosterone) play a significant role in the production of sperm. Choice A is incorrect because FSH alone is not solely responsible for sperm production. Choice B is incorrect because LH alone does not directly produce sperm. Choice C is incorrect because while testosterone is essential for sperm production, it is not the only hormone involved.

Correct Answer: C

Rationale: The myometrium is the muscle layer of the uterus responsible for contracting during labor to expel the fetus. This is essential for the birthing process. Choice A is incorrect because supporting the uterine lining is the role of the endometrium. Choice B is incorrect because facilitating implantation is mainly the function of the endometrium. Choice D is incorrect because estrogen secretion is primarily regulated by the ovaries, not the myometrium. Therefore, the correct answer is C as the myometrium's main function is to assist in the expulsion of the fetus during labor.

Correct Answer: B

Rationale: The correct answer is B: Progesterone. Progesterone helps prevent ovulation during pregnancy by maintaining the uterine lining and inhibiting the release of additional eggs. Estrogen supports the development of the uterine lining but does not directly prevent ovulation. hCG is produced by the placenta to support pregnancy but does not prevent ovulation. Testosterone is not involved in regulating ovulation during pregnancy.

Correct Answer: D

Rationale: The purpose of the bulbourethral glands is to lubricate the urethra before ejaculation. This lubrication helps to neutralize any acidic urine remnants in the urethra, providing a more suitable environment for sperm to pass through. The other choices are incorrect because: A: Sperm is produced in the testes, not the bulbourethral glands. B: Testosterone is mainly produced in the testes and adrenal glands. C: Semen is produced by the seminal vesicles, prostate gland, and sperm from the testes.