Which of the following antianginal agents is the specific bradycardic drug:

Correct Answer: D

Rationale: Step 1: Identify the specific bradycardic drug among the choices. Step 2: Atenolol is a beta-blocker known to decrease heart rate. Step 3: Bradycardia is defined as a heart rate <60 bpm. Step 4: Atenolol is commonly used to treat angina and hypertension. Step 5: Therefore, the correct answer is C: Atenolol, as it specifically decreases heart rate. Summary: A: Dipyridamole - antiplatelet, not known for bradycardic effects. B: Validol - used for angina relief, not a bradycardic agent. C: Atenolol - beta-blocker, specific bradycardic drug. D: Alinidine - antiarrhythmic agent, not primarily used for bradycardia.

Correct Answer: B

Rationale: Insulin is a polypeptide hormone, and as a protein-based molecule, it is susceptible to degradation by gastric juice, making option B correct. Gastric juice contains enzymes like pepsin that break down proteins. Option A is incorrect because polypeptides are not resistant to destruction by gastric juice. Option C is incorrect as insulin is indeed a polypeptide. Option D is incorrect as insulin is not immediately metabolized by cellular enzymes; instead, it plays a crucial role in regulating glucose metabolism.

Correct Answer: D

Rationale: The correct answer is D because the statement is false. The half-life of cortisol in circulation is around 60-90 minutes, not hours. Choice A is correct as cortisol is indeed synthesized from cholesterol. Choice B is correct as ACTH regulates cortisol secretion. Choice C is incorrect - most cortisol is inactivated in the liver.

Correct Answer: C

Rationale: The correct answer is C: Ethylenediamines; i.e. Suprastine. Ethylenediamines do not exhibit significant anticholinergic effects. Alkylamines, piperazines, and phenothiazines are known for their anticholinergic properties due to their chemical structures. Alkylamines have tertiary amines that cause anticholinergic effects. Piperazines have a bulky side chain that contributes to anticholinergic effects. Phenothiazines have a tricyclic structure that leads to anticholinergic activity. Therefore, C is the correct answer as ethylenediamines do not possess significant anticholinergic effects compared to the other categories.

Correct Answer: D

Rationale: The correct answer is D: Thiamine. Beri-beri is caused by a deficiency of thiamine (Vitamin B1), which is essential for energy metabolism and nerve function. Thiamine deficiency leads to symptoms like fatigue, muscle weakness, nerve damage, and heart problems. Riboflavin (A), Ascorbic acid (B), and Nicotinic acid (C) deficiencies do not directly cause Beri-beri. Riboflavin is important for energy production, Ascorbic acid is Vitamin C important for immunity, and Nicotinic acid is Vitamin B3 important for metabolism.