ATI RN
Test Questions on Autonomic Nervous System MCAT Questions
Question 1 of 5
The receptors for acetylcholine at the ganglia of both the sympathetic and parasympathetic divisions are:
Correct Answer: C
Rationale: Nicotinic receptors at ANS ganglia (both divisions) bind acetylcholine from preganglionic neurons. Muscarinic are postganglionic, atropine blocks muscarinic, isoproteranol is adrenergic.
Question 2 of 5
Inability to walk a straight line may indicate damage to which cranial nerve?
Correct Answer: A
Rationale: The vestibulocochlear nerve (VIII) mediates balance; damage causes ataxia (e.g., staggering gait). Others affect eye movement or tongue.
Question 3 of 5
Depolarization of the membrane of a nerve cell occurs by the rapid influx of:
Correct Answer: D
Rationale: Depolarization results from sodium (Na⁺) influx through voltage-gated channels during an action potential. Potassium (K⁺) efflux repolarizes, chloride and anions maintain resting state.
Question 4 of 5
The interior surface of the membrane of a nonconducting neuron differs from the exterior surface in that it is:
Correct Answer: A
Rationale: At rest, the interior is negatively charged (~-70 mV) with less Na⁺ and more K⁺ compared to the exterior (positive, high Na⁺), due to the sodium-potassium pump.
Question 5 of 5
The interruptions occurring at regular intervals along a myelin-coated axon are:
Correct Answer: A
Rationale: Nodes of Ranvier are gaps in the myelin sheath where action potentials regenerate, enabling saltatory conduction.