Estrogens possess immunomodulator properties but progestins do immunodepressant ones. Is it TRUE or FALSE?

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: 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.

Correct Answer: A

Rationale: Physostigmine is the correct answer as it is a cholinesterase inhibitor. Cholinesterase inhibitors prevent the breakdown of acetylcholine, leading to increased cholinergic activity. Physostigmine specifically inhibits both acetylcholinesterase and butyrylcholinesterase. This action results in increased levels of acetylcholine in the synaptic cleft, enhancing cholinergic transmission. This mechanism is used in the treatment of conditions such as myasthenia gravis and glaucoma. Selegiline (B) is a monoamine oxidase inhibitor used in the treatment of Parkinson's disease. Aminocaproic acid (C) is an antifibrinolytic agent used to treat excessive bleeding. Disulfiram (D) is an alcohol deterrent used in the management of alcohol dependence by inhibiting aldehyde dehydrogenase. These choices are incorrect as they do not act as cholinesterase inhibitors.

Correct Answer: A

Rationale: The correct answer is A: TRUE. Statins work by inhibiting HMG-CoA reductase, a key enzyme in cholesterol synthesis. This inhibition leads to upregulation of LDL receptors on hepatocytes, which increases the uptake of LDL cholesterol from the bloodstream, ultimately lowering LDL levels. Without LDL receptors, statins would not be effective. Choice B: FALSE is incorrect because statins do require LDL receptors for their mechanism of action. Choices C: All and D: None are not relevant in this context as the question is asking for a specific consideration regarding the mechanism of action of statins.

Correct Answer: D

Rationale: Step 1: Phosphorus is primarily excreted renally. Step 2: Calcitonin is a hormone that regulates calcium and phosphorus metabolism. Step 3: Calcitonin inhibits renal reabsorption of phosphorus. Step 4: Therefore, Calcitonin increases renal excretion of phosphorus. Step 5: This mechanism makes option D correct. Summary: A: Amiloride doesn't directly affect phosphorus excretion. B: Glucocorticoids affect calcium absorption, not phosphorus. C: Loop diuretics increase sodium and water excretion, not phosphorus.