Most body organs are innervated by the:

Correct Answer: C

Rationale: Most organs receive dual innervation from both sympathetic and parasympathetic divisions of the ANS, with antagonistic effects (e.g., heart, lungs). CNS is not a division.

Correct Answer: C

Rationale: Isoproterenol (isoproteranol) is a beta-adrenergic agonist, stimulating β receptors (e.g., heart, lungs). Methoxamine is α₁-specific, acetylcholine is cholinergic, atropine blocks muscarinic.

Correct Answer: B

Rationale: Atropine blocks parasympathetic muscarinic receptors, reducing vagal tone and increasing heart rate. Salivation and intestinal activity decrease, cardiac strength is unaffected.

Correct Answer: D

Rationale: Abducens (VI) innervates the lateral rectus eye muscle, not facial muscles (facial nerve, VII). Other pairings are correct.

Correct Answer: C

Rationale: The neuron is the fundamental structural and functional unit of the nervous system, encompassing axons, dendrites, and cell body. Synapses are junctions between neurons.