ATI RN
Test Questions on Autonomic Nervous System Questions
Question 1 of 5
What ion enters a neuron causing depolarization of the cell membrane?
Correct Answer: A
Rationale: Depolarization occurs when sodium (Na⁺) ions enter the neuron through voltage-gated channels, making the membrane potential more positive. Potassium exits during repolarization, and chloride or phosphate don’t typically drive depolarization.
Question 2 of 5
Which cranial nerve lies in the junction between pons and medulla?
Correct Answer: A
Rationale: The abducent nerve (CN VI) emerges at the pontomedullary junction, innervating the lateral rectus muscle. The facial (VII) and vestibulocochlear (VIII) nerves emerge from the pons, while glossopharyngeal (IX) emerges from the medulla.
Question 3 of 5
Cell bodies for the motor supply of the trigeminal nerve lie
Correct Answer: D
Rationale: The motor nucleus of the trigeminal nerve (CN V) is in the pons, near the floor of the fourth ventricle (option e). The hypothalamus and cortex don’t house motor nuclei, and the midbrain contains CN III/IV nuclei.
Question 4 of 5
with regard to myotomal nerve supply
Correct Answer: D
Rationale: Elbow extension (triceps) is a C7-C8 myotome. Opponens pollicis is C8-T1, shoulder abduction is C5-C6, and plantar flexion is S1-S2.
Question 5 of 5
A 40 year old man suffered a whiplash injury to his neck and now complains of pain along the lateral aspect of his left forearm, and there is weakness of his left biceps. What is the most likely cause of his symptoms?
Correct Answer: C
Rationale: C6 root (C5-C6 disc prolapse) supplies the lateral forearm (dermatome) and biceps (myotome via musculocutaneous nerve). C5 affects shoulder, C7 the middle finger, and C4 is higher.