Week 2 - ANS

Question 1

Trace the sympathetic preganglionic neuron from its cell body to the sympathetic chain.

Answer 1

Multipolar Cell Body in Intermediolateral Cell Column (lateral horn) → Anterior rootlet → Anterior root → Anterior rami → White ramus communicans → Paravertebral Ganglion!!!

Question 2

What course may the sympathetic preganglionic neuron take once it has entered the sympathetic chain?

Answer 2

1. Ascend to terminate in a higher paravertebral ganglion
2. Descend to terminate in a lower paravertebral ganglion
3. Traverse the sympathetic trunk without terminating (i.e. thoracic-abdominal splanchnic nerves)
4. Terminate with a postsynaptic neuron of the paravertebral ganglion at the level they enter the sympathetic chain

Question 3

What spinal cord segments give rise to sympathetic preganglionic neurons?

Answer 3

T1 - L2 (L3)

Question 4

Where do sympathetic preganglionic neurons terminate?

Answer 4

Autonomic ganglia

(paravertebral OR prevertebral ganglia)

Question 5

What spinal cord segments give rise to parasympathetic preganglionic neurons?

Answer 5

Cranial nerves: III (3), VII (7), IX (9), & X (10)

and

Sacral Nerves: S2, S3, S4

Question 6

Where are Prevertebral ganglia located?

Answer 6

Anterior surface of the abdominal aorta

(pre-aortic ganglia)

• Celiac ganglion
• Superior mesenteric ganglion
• Interior mesenteric ganglion

Question 7

Where are Paravertebral ganglia located?

Answer 7

• Segmentally allong the vertebra, except in the cervical region
• Cervical ganglia (3)
• Thoracic ganglia (12)
• Lumbar ganglia (5)
• Sacral Ganglia (5)
• Ganglion impar (1)

Question 8

How do sympathetic postganglionic neurons reach their destination in order join the spinal nerves, innervate structures in the head, and supply the heart, lungs and other thoracic structures?

Answer 8

Gray rami communicans

Question 9

What are adrenal medullary cells equivalent to?

Answer 9

Postganglionic neurons

Question 10

What neurons synapse on the adrenal gland?

Answer 10

The adrenal medullary cells receive direct input from preganglionic sympathetic neurons originating in spinal cord segments T10-L2.

Question 11

What neurotransmitter is released by the preganglionic neuron terminals?

Answer 11

ACh

Question 12

What neurotransmitter is released by postganglionic neuron terminals to the effector organ (smooth muscle, cardiac muscle, glands)?

Answer 12

Norepinephrine

Question 13

What neurotransmitter is released from adrenal medullary cells (when they act like postganglionic neurons)?

Answer 13

The adrenal medullary cells contain and release epinephrine

Question 14

What does parasympathetic stimulation lead to?

Answer 14

• Vasodilation
• Increased peristalsis
• increased secretion of gastrointestinal glands

Question 15

What does sympathetic stimulation lead to?

Answer 15

• Vasoconstriction
  
  • decreased blood flow to the skin
• Inhibition of peristalsis
• Contraction of the involuntary gastrointestinal sphincters

(piloerection, sweating, hypertension)