In passive diffusion, drugs are transported across the membrane via

Correct Answer: A

Rationale: Passive diffusion involves movement of drug molecules across the cell membrane lipid layer from an area of high concentration to low concentration, without the need for energy or carrier proteins. Lipid-soluble drugs can easily diffuse through the lipid bilayer due to their hydrophobic nature. This process is driven by the concentration gradient and follows Fick's law of diffusion. Ion channels (B) facilitate the movement of ions, not drugs. Methyl residues (C) and transport proteins (D) are not directly involved in passive diffusion of drugs.

Correct Answer: C

Rationale: Certainly! Prazosin is an alpha-1 antagonist, which means it blocks the activation of alpha-1 adrenergic receptors. By blocking these receptors, prazosin leads to vasodilation and reduced peripheral vascular resistance, ultimately lowering blood pressure. The other options are not correct because prazosin does not act as a beta-1 antagonist (B), beta-2 agonist (D), or alpha-1 agonist (A) in the context of treating hypertension.

Correct Answer: B

Rationale: The correct answer is B: Increase of bronchial secretion. Parasympathetic stimulation activates the vagus nerve, leading to bronchial smooth muscle relaxation and increased secretion to facilitate breathing. This response helps in clearing the airways and optimizing gas exchange. Choices A, C, and D are incorrect because parasympathetic stimulation typically does not lead to an increase in intestinal motility (A), contraction of the iris sphincter muscle causing miosis (C), or a decrease in heart rate (D), as these are more characteristic of sympathetic stimulation.

Correct Answer: A

Rationale: Step 1: Nicotinic AChRs are ion channels that allow the passage of ions across the cell membrane in response to acetylcholine. Step 2: The ion channels are not protein-bound or slow, so option B is incorrect. Step 3: Nicotinic AChRs are not G-coupled receptors, so option C is incorrect. Step 4: Nicotinic AChRs are located on the cell membrane, making them water-soluble, so option A is correct. Step 5: Nicotinic AChRs are not intracellular receptors, so option D is incorrect.

Correct Answer: C

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.