Mechanism of aspirin action is:

Correct Answer: B

Rationale: The correct answer is B because aspirin inhibits cyclooxygenase (COX) enzyme, which is responsible for thromboxane synthesis. Thromboxane promotes platelet aggregation and vasoconstriction. By inhibiting thromboxane synthesis, aspirin reduces platelet aggregation, making it an effective antiplatelet agent. Choice A is incorrect because plasminogen is not involved in the mechanism of aspirin action. Choice C is incorrect because it describes the mechanism of heparin, not aspirin. Choice D is incorrect because inhibiting the glycoprotein IIb/IIIa complex is the mechanism of action of drugs like abciximab, not aspirin.

Correct Answer: C

Rationale: The correct answer is C because angiotensin II is more potent than angiotensin I. Angiotensin II is a peptide hormone that stimulates aldosterone secretion and acts as a potent vasoconstrictor. Angiotensin I is an inactive precursor that is converted to angiotensin II by the enzyme ACE. Angiotensin II is more biologically active and has stronger effects on vasoconstriction and aldosterone release compared to angiotensin I. Therefore, statement C is false as angiotensin II is more potent than angiotensin I.

Correct Answer: A

Rationale: The correct answer is A: Growth hormone-releasing hormone (GHRH). The hypothalamus, not a gland, produces GHRH to stimulate the pituitary gland to release growth hormone. Choice B (FSH) is produced by the anterior pituitary gland. Choice C (Aldosterone) is produced by the adrenal glands. Choice D (Estradiol) is a form of estrogen produced by the ovaries. Therefore, only choice A aligns with the role of the hypothalamus in regulating hormone release.

Correct Answer: B

Rationale: The correct answer is B because chlorpropamide has a longer duration of action compared to tolbutamide. Chlorpropamide has a half-life of around 36 hours, whereas tolbutamide's half-life is about 5 hours. This means that chlorpropamide stays in the body and continues to lower blood sugar levels for a longer period of time compared to tolbutamide. Choices A and C are incorrect as they suggest that the durations of action are equal or that tolbutamide has a longer duration, which is not the case based on their pharmacokinetics. Choice D is also incorrect as it does not address the specific comparison between tolbutamide and chlorpropamide.

Correct Answer: A

Rationale: The correct answer is A: Ibuprofen. Ibuprofen is a propionic acid derivative due to its chemical structure. It belongs to the same class of NSAIDs as naproxen and ketoprofen, which are also propionic acid derivatives. Ibuprofen works by inhibiting the enzyme cyclooxygenase, thereby reducing inflammation, pain, and fever. Choice B, Indomethacin, is incorrect as it is an acetic acid derivative. Choice C, Metamizole (Analgin), is incorrect as it is a pyrazolone derivative. Choice D, Diclofenac, is incorrect as it is an acetic acid derivative.