Dopamine at medium doses influences mainly:

Correct Answer: C

Rationale: The correct answer is C: Beta-1 adrenoreceptors (leads to enhanced cardiac output). Dopamine at medium doses mainly influences the Beta-1 adrenoreceptors in the heart, leading to increased heart rate and contractility, thus enhancing cardiac output. This is because dopamine acts as a positive inotropic and chronotropic agent on the heart. Choices A and B are incorrect because dopamine does not primarily act on Alfa-adrenoreceptors (A) causing peripheral vasoconstriction or dopamine receptors (B) causing vasodilation of renal and mesenteric vessels at medium doses. Choice D is incorrect because dopamine at medium doses primarily influences Beta-1 adrenoreceptors, not all the options listed.

Correct Answer: D

Rationale: The correct answer is D because the statement is false. The triphasic pill does not contain luteinizing hormone (LH). The triphasic pill contains varying levels of estrogen and progestin throughout the cycle to mimic the natural hormonal fluctuations in a woman's menstrual cycle. A: The combination pill does contain both estrogen and progestin, making statement A true. B: Ethinyl estradiol and mestranol are indeed commonly used in oral contraceptives, making statement B true. C: The minipill contains progestin alone, making statement C true. In summary, the incorrect statement is D because the triphasic pill does not contain luteinizing hormone. Statements A, B, and C are all true regarding oral contraceptives.

Correct Answer: B

Rationale: The correct answer is B because immunodeficiency refers to a disorder or deficiency in the normal immune response. This means that the immune system is not functioning properly, leading to increased susceptibility to infections and other health issues. Choice A describes inflammation, not immunodeficiency. Choice C describes autoimmune disease, which is different from immunodeficiency. Choice D is incorrect because not all the statements are related to immunodeficiency. In summary, the correct answer is B because it directly relates to a malfunction in the immune system, while the other choices describe different processes or conditions.

Correct Answer: A

Rationale: The correct answer is A because antienzymes are agents that inhibit or destroy enzymic activity. They can be inhibitory enzymes or antibodies that target specific enzymes. This definition aligns with the concept of antienzymes acting to retard or inhibit enzymatic activity. Choice B is incorrect because substances that prevent vitamins from exerting their effects are not related to antienzymes. Choice C describes enzymes, not antienzymes, which are the opposite in function. Choice D refers to coenzymes, which are required for enzyme activity, not antienzymes that inhibit or destroy enzymic activity.

Correct Answer: D

Rationale: Step-by-step rationale for the correct answer (D): 1. Aminoglutethimide is an aromatase inhibitor used in cancer therapy. 2. Aromatase inhibitors block the enzyme aromatase, which converts androgens to estrogens. 3. By inhibiting aromatase, aminoglutethimide reduces estrogen production, beneficial in hormone-sensitive cancers. 4. Physostigmine (A) is a cholinesterase inhibitor, Allopurinol (B) is a xanthine oxidase inhibitor, and Aminocaproic acid (C) is an antifibrinolytic agent, not aromatase inhibitors.