Side effect of nitrates and nitrite drugs are, EXCEPT:

Correct Answer: B

Rationale: The correct answer is B: GI disturbance. Nitrates and nitrites primarily affect the cardiovascular system by dilating blood vessels, leading to vasodilation and decreased cardiac workload. GI disturbances are not commonly associated with these drugs. A: Orthostatic hypotension, tachycardia, C: Throbbing headache, and D: Tolerance are all known side effects of nitrates and nitrites due to their cardiovascular effects.

Correct Answer: C

Rationale: The correct answer is C because the secretion of thyrotropin (TSH) is regulated by a negative feedback loop. When the concentration of thyroid hormones in the blood decreases, the hypothalamus signals the pituitary gland to release more TSH to stimulate the thyroid gland to produce more thyroid hormones. Conversely, when the thyroid hormone levels are high, TSH secretion is inhibited. Choices A and B are incorrect because the amount of iodine and thyroid hormones in the thyroid gland itself does not directly regulate TSH secretion. Choice D is incorrect as catecholamines do not directly influence TSH secretion.

Correct Answer: A

Rationale: Estrogens have immunomodulatory properties by enhancing immune responses, while progestins have immunosuppressive effects by inhibiting immune responses. Therefore, the statement is TRUE. Choice B is incorrect because the statement is not false. Choice C is incorrect as it does not provide a clear answer. Choice D is incorrect as it does not apply in this scenario.

Correct Answer: B

Rationale: The correct answer is B because adaptive immunity is characterized by antigen-specific defense mechanisms that target and eliminate specific pathogens. This type of immunity takes time to develop, usually several days, and involves the activation of lymphocytes such as T and B cells that can recognize and respond to specific antigens. This process leads to the formation of memory cells that provide long-lasting protection against future encounters with the same antigen. Choices A, C, and D are incorrect: A: This describes innate (natural) immunity, which is present at birth and provides immediate, nonspecific defense mechanisms against pathogens. C: Interferons are signaling proteins produced in response to viral infections and are part of the innate immune response, not adaptive immunity. D: Immunosuppressive agents are drugs that suppress the immune system and are used to prevent rejection of transplanted organs or treat autoimmune diseases. They do not enhance adaptive immunity.

Correct Answer: C

Rationale: The correct answer is C because it accurately defines what vitamins are: essential organic substances needed in small amounts for normal growth and activity. Vitamins are obtained naturally from plant and animal foods. Choice A is incorrect because vitamins are organic, not inorganic. Choice B is incorrect because vitamins are needed in small quantities, not very large. Choice D is incorrect because vitamins are not products of endocrine gland secretion.