Spinal Nerves

Question 1

Draw out a cross-section of the spinal cord, and label the spinal roots, spinal rami, and neurons.

Answer 1

Refer to Notion.

Question 2

What do the dorsal and ventral rami supply?

Answer 2

• Dorsal trunk
• Ventral trunk + limbs

Question 3

Describe the anatomy of the sympathetic nervous system.

Answer 3

1. Preganglionic neurons leave spinal cord via ventral roots of T1 to L2
2. Travel through ventral rami to synapse on paravertebral ganglia (sympathetic trunk)
3. Some do not synapse here, but instead on prevertebral ganglia closer to the target organs (splanchnic nerves)
4. Postganglionic fibers synapse onto target organs, or loop back through dorsal rami to the spinal cord

Question 4

Describe the anatomy of the parasympathetic nervous system.

Answer 4

Cranial Outflow
1. Preganglionic neurons exit brainstem via cranial nerves
2. Synapse on ganglia close to their target organs
3. Postganglionic fibers synapse on target organs

Sacral Outflow
1. Preganglionic neurons exit spinal cord via S2- S4
2. Directly synapse onto target organs (pelvic splanchnic nerves)