Which of the following evidences anticholinergic side effects:

Correct Answer: D

Rationale: The correct answer is D: Tachycardia. Anticholinergic medications block the action of acetylcholine, leading to increased heart rate (tachycardia) by inhibiting the parasympathetic nervous system. Excessive salivation (choice A) is a cholinergic effect, not anticholinergic. Bradycardia (choice B) is not consistent with anticholinergic side effects. Diarrhea and colic (choice C) are more commonly associated with cholinergic, not anticholinergic, effects.

Correct Answer: D

Rationale: Step-by-step rationale: 1. Isoprenaline is a beta-adrenergic agonist. 2. It directly stimulates beta adrenoceptors, leading to effects like increased heart rate. 3. Isoprenaline causes bronchodilation by relaxing bronchial smooth muscles. 4. It also causes vasodilation, leading to decreased blood pressure. 5. Isoprenaline does not have a direct effect on intestinal motility, making option D incorrect. Summary: Option D is incorrect as isoprenaline does not increase intestinal motility. Options A, B, and C are correct as isoprenaline directly stimulates beta adrenoceptors, relaxes bronchial smooth muscles, and decreases blood pressure, respectively.

Correct Answer: C

Rationale: The correct answer is C - Phentolamine plus propranolol. Phentolamine is an alpha-adrenergic blocker that can counteract the effects of high noradrenaline levels, while propranolol is a non-selective beta blocker that can further control the symptoms by blocking beta-adrenergic receptors. Combining both drugs can effectively block all adrenergic receptors and normalize the signs and symptoms of pheochromocytoma. A: Propranolol alone cannot block all adrenergic receptors, as it only targets beta receptors. B: Phentolamine alone can block alpha receptors but does not address the beta receptors. D: Atropine plus phenylephrine combination does not cover all adrenergic receptors involved in pheochromocytoma.

Correct Answer: D

Rationale: The correct answer is D because X, a mixture of amphetamines, works by releasing neuronal noradrenaline, causing excessive sympathetic effects like severe rises in blood pressure. This is how the drug helps manage ADHD symptoms. The other choices are incorrect because A (blocking muscarinic receptors) would not be related to the autonomic effects seen with X, B (blocking β2 receptors) would not explain the fatal autonomic effects, and C (inhibiting MAO) would not lead to the described autonomic effects. Therefore, D is the correct choice based on how X works in the body to produce its effects on the sympathetic nervous system.

Correct Answer: B

Rationale: The correct answer is B: a length of DNA that codes for a protein. Genes are specific sequences of DNA that encode instructions for building proteins. This is the fundamental role of genes in the process of protein synthesis. Choice A is incorrect because not all DNA in a cell controls metabolic reactions; some DNA is non-coding. Choice C is incorrect as it refers to the entire nucleus and its contents, not just the gene. Choice D is incorrect as genes do not solely determine the inheritance of sex; they also code for other traits. In summary, the definition of a gene as a segment of DNA that codes for a protein aligns with the known function and role of genes in genetics and molecular biology.