Least Splanchnic Nerve Flashcards

Trace the least thoracic splanchnic nerve from its sympathetic origin to the renal plexus, examining its course and visceral connections.

Card 1 of 20Question

What is the least splanchnic nerve?

A paired thoracic splanchnic nerve carrying predominantly preganglionic sympathetic fibers toward the renal autonomic plexus.

In This Section

1. What is the least splanchnic nerve?

A paired thoracic splanchnic nerve carrying predominantly preganglionic sympathetic fibers toward the renal autonomic plexus.

2. Which thoracic sympathetic ganglion typically gives rise to the least splanchnic nerve?

The twelfth thoracic sympathetic ganglion (T12).

3. Which division of the autonomic nervous system is represented by the least splanchnic nerve?

The sympathetic division.

4. Where are the cell bodies of preganglionic sympathetic neurons contributing to the least splanchnic nerve?

In the intermediolateral cell column of the thoracolumbar spinal cord.

5. Do preganglionic fibers of the least splanchnic nerve normally synapse in the thoracic sympathetic trunk?

No. They pass through the paravertebral sympathetic ganglia without synapsing.

6. In which anatomical compartment does the least splanchnic nerve begin its course?

The posterior mediastinum.

7. In which direction does the least splanchnic nerve travel toward the diaphragm?

Inferomedially from the lower thoracic sympathetic trunk.

8. How does the least splanchnic nerve typically enter the abdomen?

It passes through or behind the corresponding diaphragmatic crus.

9. Which major autonomic plexus receives fibers from the least splanchnic nerve?

The renal plexus.

10. Which prevertebral ganglia may receive sympathetic fibers from the least splanchnic nerve?

The aorticorenal and renal ganglia.

11. Where is the renal plexus located?

Around the renal artery and its branches near the renal hilum.

12. How do postganglionic sympathetic fibers associated with the least splanchnic nerve reach the kidneys?

They follow the renal arteries and their branches through periarterial nerve plexuses.

13. What is the general effect of sympathetic stimulation on renal blood vessels?

Vasoconstriction, which can reduce renal blood flow.

14. Which renal cells respond to sympathetic stimulation by releasing renin?

The juxtaglomerular granular cells.

15. Which visceral sensory fibers may accompany the least splanchnic nerve toward the spinal cord?

Visceral pain afferent fibers from the kidney and associated upper urinary tract structures.

16. Do visceral pain afferent fibers traveling through the least splanchnic nerve synapse in prevertebral ganglia?

No. They pass through sympathetic ganglia without synapsing.

17. How does the usual spinal origin of the least splanchnic nerve differ from that of the lesser splanchnic nerve?

The least typically arises from T12, whereas the lesser typically arises from T10 and T11.

18. What anatomical variation commonly affects the least splanchnic nerve?

It may be absent or incorporated into the lesser splanchnic nerve.

19. Why is the least splanchnic nerve relevant during operations near the upper renal vessels?

Its connections with the renal and aorticorenal plexuses may be encountered during retroperitoneal dissection.

20. Which neurotransmitter is released by preganglionic sympathetic fibers of the least splanchnic nerve?

Acetylcholine.