Autonomic Nervous System

Question 1

Name the X2 divisions of the ANS.

Answer 1

1) Sympathetic

2) Parasympathetic

Question 2

Where do the nerves of the SNS arise from?

What is their distribution?

Answer 2

T1 - L2

All parts of the body wall and viscera.

Question 3

Where do the nerves of the PNS arise from?

What is their distribution?

Answer 3

Arise cranio-sacrally:
= cranial nerves 3, 7, 9 & 10
= S2 - S4

Distribution = head & trunk only.

Question 4

In the ANS motor fibres, which neurons are myelinated and which are not?

What about somatic neurons?

Answer 4

Pre-ganglionic = myelinated

Post-ganglionic = unmyelinated

Somatic = single neuron which is fully myelinated

Question 5

In terms of the spinal cord, where are grey and white matter located and what do they consist of?

Answer 5

Grey = centrally = somas

White = peripherally = axons

Question 6

What is the name of the group of fibres leaving the spinal cord posteriorly?

What about anteriorly?

Answer 6

Dorsal root.

Ventral root.

Question 7

Where are sensory fibre ganglia located (both somatic and autonomic)?

Answer 7

In dorsal root ganglia.

Question 8

What do the dorsal and ventral root fibres join to form?

Where does this exit the vertebrae?

Answer 8

A spinal nerve exiting the vertebra from the intervertebral foramina.

Question 9

What do spinal nerves branch into?

Answer 9

Anterior and posterior rami.

Question 10

Where do SNS motor neurons travel in relation to the spinal cord?

Answer 10

Pre-ganglionically their cell bodies are located in the CNS. They exit via the anterior root until they reach the spinal nerve where they exit via the white ramus communicantes. They synapse at the sympathetic chain which runs paravertebrally at the back of the chest wall. The post-ganglionic neurons then re-enter at the relevant level via the grey rami communicantes and continue to the effector tissue.