What type of receptor requires an effector protein to initiate a signal?

Correct Answer: D

Rationale: Metabotropic receptors require effector proteins (e.g., G-proteins) to initiate intracellular signaling cascades. Ionotropic receptors are ligand-gated channels that don’t use effector proteins.

Correct Answer: D

Rationale: The lumbar plexus (L1-L4) forms the femoral nerve from L2-L3-L4, innervating thigh muscles. It’s lateral to the inferior vena cava, formed from anterior rami, and includes more than the last three lumbar nerves.

Correct Answer: D

Rationale: The facial nerve (CN VII) motor nucleus is in the pons, controlling facial muscles. The midbrain houses CN III/IV nuclei, and the cerebellum coordinates movement.

Correct Answer: D

Rationale: Corneal sensation (via ophthalmic nerve, V1) synapses in the trigeminal ganglion, the sensory root of CN V.

Correct Answer: C

Rationale: The cervical sympathetic trunk lies behind the carotid sheath, ascending along the neck to the superior cervical ganglion.