Advanced Nerve Supply of the Adrenal Glands Quiz

Q1. Why is the adrenal medulla considered an exception to the usual two-neuron sympathetic efferent pathway?

• The pathway uses somatic motor neurons
• The pathway contains no preganglionic neuron
• The medulla is supplied only by parasympathetic fibers
• The endocrine chromaffin cell replaces the conventional postganglionic neuron

Q2. What embryologic fact supports the classification of chromaffin cells as modified sympathetic neurons?

• Both develop from renal tubular epithelium
• Both are derived from intermediate mesoderm
• Both are derived from endoderm
• Both chromaffin and sympathetic ganglion cells are neural crest-derived

Q3. Why can activation of a relatively localized adrenal neural pathway produce body-wide effects?

• The adrenal gland controls all spinal motor neurons
• Adrenal nerves directly innervate every peripheral organ
• Chromaffin cells send axons throughout the body
• The neural signal triggers circulating catecholamine release

Q4. How do preganglionic sympathetic fibers differ from ordinary abdominal splanchnic fibers destined for vascular smooth muscle?

• Ordinary abdominal sympathetic fibers never synapse
• Adrenal fibers originate in dorsal root ganglia
• Adrenal fibers bypass the prevertebral ganglionic synapse and terminate directly on chromaffin cells
• Adrenal fibers are parasympathetic

Q5. What receptor mechanism makes adrenal medullary transmission resemble transmission in an autonomic ganglion?

• Postganglionic norepinephrine activates mineralocorticoid receptors
• Preganglionic acetylcholine activates nicotinic receptors
• ACTH activates muscarinic receptors
• Cortisol activates voltage-gated sodium channels

Q6. Why can sympathetic activation cause adrenal catecholamine secretion within seconds?

• The adrenal cortex must generate action potentials for several hours
• Steroid hormones must first be stored in vesicles
• Direct synaptic depolarization triggers rapid granule exocytosis
• New chromaffin cells must first develop

Q7. Which neural pathway carries visceral sensory information from the adrenal region back toward the spinal cord?

• Visceral afferents traveling with sympathetic pathways
• Optic nerve fibers
• Somatic motor fibers in the femoral nerve
• Parasympathetic fibers in pelvic splanchnic nerves only

Q8. Why should adrenal cortical secretion not be described as primarily under direct sympathetic neural control?

• All cortical hormones are stored in sympathetic neurons
• The cortex is outside the autonomic nervous system anatomically
• The cortex contains no living cells
• Cortical zones are controlled mainly by endocrine and humoral signals

Q9. How does the nerve supply complement the adrenal medulla's vascular anatomy?

• Nerves direct catecholamines into the renal pelvis
• Neural activation is coupled to rapid vascular delivery of catecholamines
• Neural stimulation closes all adrenal vessels
• The medulla is avascular during sympathetic activation

Q10. Which statement best integrates the nerve supply of the adrenal glands?

• The adrenal glands have no visceral afferent or autonomic connections
• All adrenal innervation is somatic and travels through lumbar plexus nerves
• Both cortex and medulla are controlled primarily by postganglionic parasympathetic fibers
• The medulla receives direct preganglionic sympathetic secretomotor input, while the cortex is regulated mainly by endocrine and humoral mechanisms