Histology: Autonomic Nervous System

Question 1

What neurotransmitters act in the parasympathetic division of the ANS?

Answer 1

Preganglionic fibers release ACh. Post-ganglionic fibers release ACh or NE at effector. Typically the sympathetic division secretes NE and the parasympathetic division secretes ACh at the postganglion.

Question 2

How do neurons differ in the somatic nervous system in the ANS?

Answer 2

Somatic nerves have one single neuron from the CNS with a heavily myelinated axon, are only stimulatory and they secrete ACh. Autonomic signals can be stimulatory or inhibitory and are sent through a two neuron chain with myelinated preganglionic neurons and unmyelinated post-ganglionic neurons.

Question 3

How does the anatomy of parasympathetic and sympathetic nerve fibers differ?

Answer 3

Parasympathetic fibers are located craniosacrally with ganglia in their effector organs. They have a long preganglionic fiber and a short post-ganglionic fiber. Sympathetic fibers are located in the thoracolumbar region with ganglia near the spinal cord and have short preganglionic fibers with long post-ganglionic fibers.

Question 4

What cranial nerves are associated with the parasympathetic nervous system? Sacral nerves?

Answer 4

Occulomotor (III), Facial (VII), Glossopharyngeal (IX) and Vagus (X). S2-S4

Question 5

What forms the lateral horns of the spinal cord?

Answer 5

Sympathetic neurons.

Question 6

Where do sympathetic preganglionic fibers go after the lateral horns of the spinal cord?

Answer 6

Through the white rami communicantes and into the paravertebral ganglia.

Question 7

What are the two types of cholinergic receptors?

Answer 7

Muscarinic and nicotinic

Question 8

How do blood pressure medications work?

Answer 8

They interfere with alpha-receptors in the sympathetic nervous system to decrease blood pressure.

Question 9

What is the main integrative center of the ANS?

Answer 9

Hypothalamus

Question 10

Why do older people struggle more with constipation?

Answer 10

The ANS deteriorates as you get older

Question 11

Answer 11

1. Sensory afferent fibers 2. Motor efferent fibers 3. Vertebral body 4. White matter 5. Gray matter 6. Anterior spinal nerve root 7. Posterior spinal nerve root. 8. DRG 9. Spinal nerve 10. Dorsal rami 11. Ventral rami 13. White rami communicantes 14. Gray rami communicante 15. Paravertebral ganclia