Nerves of the Abdomen

Question 1

Through what nerve does autonomic preganglionic fibers travel to the GI tract?

Answer 1

Via a cranial nerve or one of the thoracic or pelvic splanchnic nerves.

Question 2

Where do autonomic preganglionic fibers go in the abdomen?

Answer 2

They either synapse or pass through the pre-aortic ganglia or plexuses.

Question 3

What are post-ganglionic sympathetic and preganglionic parasympathetic fibers carried in?

Answer 3

Periarterial plexuses to their target organ.

Question 4

Where do postganglionic parasympathetic fibers synapse?

Answer 4

On small enteric ganglia in the organ wall.

Question 5

What are the visceral efferents?

Answer 5

Two neuron chain between CNS and the effector organ (e.g., smooth muscle, glands, cardiac muscle)

Question 6

Where do the visceral efferents synapse?

Answer 6

Ganglion

Question 7

What nerve fibers are myelinated and unmyelinated?

Answer 7

• Preganglionic nerve fiber (axon) = myelinated

- Postganglionic fiber = unmyelinated

Question 8

What is the general sympathetic pathway?

Answer 8

CNS –> preganglionic fiber which releases ACh onto Autonomic ganglion –> message sent into postganglionic fiber –> releases NE

Question 9

Where do preganglionic fibers’ cell bodies lie? How long are they?

Answer 9

In the thoracolumbar lateral horn. They are relatively short.

Question 10

A single symphathetic preganglionic axon has ____________ and may synapse with _____ postganglionic neurons.

Answer 10

• Many collateral branches

- 20 or more