A man is taking a number of medications, one of which appears to be interfering with the emission phase of the sexual act. Which of the following medications could cause this problem?

Correct Answer: B

Rationale: The correct answer is B because blocking the smooth muscle receptors for nitric oxide would interfere with vasodilation necessary for an erection during the emission phase of the sexual act. Choice A would actually enhance the effects of nitric oxide, Choice C would increase nitric oxide release which would typically improve sexual function, and Choice D, a testosterone-like androgen compound, would not directly affect the emission phase related to nitric oxide.

Correct Answer: C

Rationale: The correct answer is C because oxytocin is responsible for stimulating the contraction of myoepithelial cells around the alveoli in the mammary glands, causing milk ejection. This process is known as the let-down reflex. In contrast, choice A (myoepithelial cells must relax) is incorrect because they need to contract to push milk out. Choice B (prolactin levels must fall) is incorrect because prolactin is responsible for milk production, not milk ejection. Choice D (the baby's mouth must develop a strong negative pressure over the nipple) is incorrect because it is the mother's hormone release, not the baby's action, that causes milk flow.

Correct Answer: D

Rationale: The correct answer is D: Prostate. The prostate gland surrounds the upper portion of the urethra just below the junction with the urinary bladder. It secretes a fluid that makes up a significant portion of semen. The other choices are incorrect because: A: Ejaculatory gland is not a correct anatomical structure. B: Seminal vesicles are located behind the bladder and contribute to semen production. C: Bulbourethral glands are located at the base of the penis and secrete a lubricating fluid during arousal.

Correct Answer: B

Rationale: The correct answer is B: zygote. A zygote is formed when a sperm cell fertilizes an egg cell, marking the beginning of a new individual's development. It is the first cell of the new organism with a full set of chromosomes. A: Blastocyst is a later stage of development after the zygote has undergone several cell divisions. C: Fetus refers to the later stages of development when the embryo has developed recognizable features. D: Embryo is the stage after the zygote when the cells start to differentiate into different tissues and organs.

Correct Answer: C

Rationale: The correct answer is C, the uterine (fallopian) tubes. This is where fertilization usually occurs as it is the site where the egg and sperm meet. The egg is released from the ovary and travels through the fallopian tube where it can be fertilized by sperm. If fertilization occurs, the resulting embryo will then travel to the uterus for implantation. The other choices are incorrect because fertilization does not typically occur in the ovary (A) or vesicular (Graafian) follicle (B). While the uterus (D) is where the embryo implants and develops into a fetus, fertilization itself does not occur there.