Nerve Supply of the Adrenal Glands Flashcards

Study adrenal gland innervation, including sympathetic pathways, splanchnic nerves, chromaffin cells, and catecholamine release.

Card 1 of 24Question

Which division of the autonomic nervous system provides the principal secretomotor innervation of the adrenal glands?

The sympathetic nervous system.

In This Section

1. Which division of the autonomic nervous system provides the principal secretomotor innervation of the adrenal glands?

The sympathetic nervous system.

2. Which region of the adrenal gland receives direct preganglionic sympathetic innervation?

The adrenal medulla.

3. Which nerves carry most preganglionic sympathetic fibers to the adrenal medulla?

The thoracic splanchnic nerves, particularly the greater splanchnic nerve.

4. From which spinal cord segments do the greater thoracic splanchnic nerves typically originate?

The T5 to T9 thoracic spinal segments, with anatomical variation.

5. Where are the cell bodies of preganglionic sympathetic neurons supplying the adrenal medulla located?

In the intermediolateral cell column of the thoracic spinal cord.

6. Through which spinal nerve branches do preganglionic sympathetic fibers enter the sympathetic trunk?

The white rami communicantes.

7. Do preganglionic sympathetic fibers supplying the adrenal medulla synapse in the sympathetic trunk?

No. They pass through the sympathetic trunk without synapsing.

8. Do sympathetic fibers destined for adrenal chromaffin cells normally synapse in the celiac ganglia?

No. They pass through the prevertebral ganglia without synapsing.

9. What autonomic nerve network contributes fibers to the suprarenal plexus?

The celiac plexus.

10. Which cells receive the preganglionic sympathetic fibers within the adrenal medulla?

Chromaffin cells.

11. What is the functional neuronal equivalent of an adrenal chromaffin cell?

A modified postganglionic sympathetic neuron.

12. Which neurotransmitter is released by preganglionic sympathetic fibers onto chromaffin cells?

Acetylcholine.

13. Which receptors on chromaffin cells mediate their response to acetylcholine?

Neuronal nicotinic acetylcholine receptors.

14. What intracellular event follows nicotinic receptor activation in adrenal chromaffin cells?

Membrane depolarization and an increase in intracellular calcium.

15. How does sympathetic stimulation trigger catecholamine release from the adrenal medulla?

Calcium-dependent exocytosis of catecholamine-containing secretory granules.

16. Which two catecholamines are released during sympathetic stimulation of the adrenal medulla?

Epinephrine and norepinephrine.

17. How does adrenal medullary secretion differ from neurotransmitter release by typical sympathetic neurons?

Chromaffin cells release catecholamines directly into the bloodstream rather than at peripheral neuroeffector junctions.

18. What is the principal physiological response mediated by sympathetic activation of the adrenal medulla?

The systemic fight-or-flight response to acute stress.

19. Does the adrenal cortex receive the same direct secretomotor sympathetic innervation as the medulla?

No. Cortical steroid secretion is primarily regulated by circulating hormones rather than direct neural stimulation.

20. Which pituitary hormone regulates cortisol secretion independently of direct adrenal medullary innervation?

Adrenocorticotropic hormone (ACTH).

21. Which signaling mechanisms primarily regulate aldosterone secretion from the adrenal cortex?

Angiotensin II and changes in extracellular potassium concentration.

22. What is the principal role of sympathetic nerve fibers associated with adrenal blood vessels?

Regulation of vascular smooth muscle tone and local blood flow.

23. Is there an established direct parasympathetic secretomotor supply to adrenal chromaffin cells?

No. Their established direct secretomotor innervation is sympathetic.

24. What embryological origin explains the neuronal characteristics of adrenal chromaffin cells?

Neural crest cells, which also give rise to many peripheral autonomic neurons.