Actions of oxytocin include the following except:

Correct Answer: A

Rationale: 1. Oxytocin is a hormone that primarily functions in inducing uterine contractions and milk let-down. 2. Vasoconstriction is not a known physiological action of oxytocin. 3. Increased water reabsorption, mammary contraction, and prostaglandin release are all effects of oxytocin. 4. Therefore, the correct answer is A: Vasoconstriction, as it is not a typical action of oxytocin.

Correct Answer: B

Rationale: The correct answer is B: Disruption of cyclic menstrual bleeding. Injectable contraceptive depot medroxyprogesterone acetate can cause irregular menstrual bleeding patterns, such as prolonged spotting or amenorrhea. This occurs due to the suppression of ovulation and the thinning of the endometrial lining. Nausea and vomiting (choice A) are less common side effects and usually subside after the initial injections. Venous thrombosis (choice C) and hypertension (choice D) are more associated with combined hormonal contraceptives containing estrogen.

Correct Answer: D

Rationale: The correct answer is D because the progestin component of the combined pill serves multiple purposes. Firstly, it suppresses ovulation by inhibiting the release of an egg from the ovary, preventing pregnancy. Secondly, it helps induce prompt bleeding at the end of the pill course, mimicking a natural menstrual cycle. Lastly, progestin also blocks the increased risk of endometrial carcinoma associated with unopposed estrogen use. Therefore, all of the choices A, B, and C are correct in relation to the purposes served by the progestin component.

Correct Answer: A

Rationale: Step 1: Mifepristone is a progesterone receptor antagonist. Step 2: In the late luteal phase, progesterone levels drop, leading to menstruation. Step 3: By inhibiting progesterone action, mifepristone induces menstruation. Step 4: Therefore, the correct answer is A - induces menstruation. Summary: B is incorrect as mifepristone does not postpone menstruation. C is incorrect as it does not prevent luteolysis but rather triggers it. D is incorrect as mifepristone does not cause decidualization of endometrium.

Correct Answer: D

Rationale: The correct answer is D, "All of the above." Norethindrone, Nafarelin, and Danazol are all beneficial in managing endometriosis. Norethindrone is a progestin that helps regulate menstrual cycles and reduce pain. Nafarelin is a gonadotropin-releasing hormone agonist that suppresses ovarian function, reducing estrogen levels. Danazol is a synthetic androgen that suppresses estrogen production and inhibits the growth of endometrial tissue. Therefore, all three medications address different aspects of endometriosis, making them effective treatment options.