WORKSHEET 10: THE AUTONOMIC NERVOUS SYSTEM

***PREAORTIC GANGLIA are also known as PREVERTEBRAL GANGLIA*** Collectively, all preaortic/prevertebral ganglia are what are known as COLLATERAL GANGLIA .

*** DO NOT ASSUME THAT SYMPATHETIC DIVISION CAUSES EXCITATION AND PARASYMPATHETIC DIVISION CAUSES INHIBITION. THIS IS NOT 100% ACCURATE.***

What are the two divisions of the autonomic nervous system?

Parasympathetic: craniosacral divison

Sympathetic: thoracolumbar division

What are the two physical parts of each component of the ANS?

Neuronsàganglia (preganglionic)

Ganglia àtarget organs (postganglionic)

Which cranial nerves carry parasympathetic fibers?

CN III, VII, IX, X

Compare and contrast the sympathetic nervous system and the parasympathetic nervous system in the following chart.

Parasympathetic Nervous System / Sympathetic Nervous System
Origin / CN III, VII, IX, X and spinal nerves S2-S4 / Spinal nerves T2-L2
Length of preganglionic fibers / Long / Short
Neurotransmitter released at ganglia/effect / Ach
Excitatory / Ach
Excitatory
Ganglia location / Near or Within Target organ / Sympathetic ganglia
Collateral ganglia
Length of postganglionic fibers / Very short / Long
Neurotransmitter released at target organ/effect / Ach
MOSTLY inhibitory / Ne
MOSTLY excitatory
Target organs / Glands and organs of head and neck, thoracic, abdominal, and pelvic organs / Arrector pilli muscle, sweat glands, skin, blood vessels, thoracic and abdominal and pelvic visceral organs

What are the effects of sympathetic stimulation?

Increased energy

Increased HR, BP, breathing rate

Increased muscle tone

Increased use of energy reserves (breakdown of glycogen from liver and fat from adipose tissue)


What are the effects of parasympathetic stimulation?

Increased activity in salivary glands

Increased contractions in GI tract

Stimulation of defecation and micturition

Decreased HR, BP, breathing rate

Sexual arousal

What is the main difference between the synapse of sympathetic nerves going to heart and lungs and the ones going to abdominal organs?

The difference is the location of synapse. Sympathetic nerves going to thoracic organs and the head and neck will go synapse at the sympathetic chain ganglia. After that synapse, postganglionic fibers will go to head, neck, and thoracic organs.

Sympathetic nerves going to abdominal organs will bypass the sympathetic ganglia and unite to form several splanchnic nerves that will then synapse at collateral ganglia (celiac ganglion, superior mesenteric ganglion and inferior mesenteric ganglion).

List the GANGLIA where preganglionic fibers of the parasympathetic nervous system synapse and the organs/structures where postganglionic fibers head to after that synapse.

CN IIIàciliary ganglionàintrinsic muscles of the eye

CN VIIàpterygopalantine ganglion & submandibular ganglionàlacrimal glands and salivary glands

CN IXàotic ganglionàparotid gland

CN Xàintramural gangliaàthoracic and abdominal viscera

Spinal nerves S2-S4àintramural gangliaàpelvic viscera

List the GANGLIA where preganglionic fibers of the sympathetic nervous system synapse and the organs/structures where postganglionic fibers head to after that synapse.

Sympathetic chain gangliaà organs of head and neck, thoracic viscera like the heart and lungs

Collateral ganglia

Celiac ganglionàstomach, gallbladder, spleen, pancreas, duodenum

Superior mesenteric ganglionàSmall intestine, part of large intestine

Inferior mesenteric ganglionàrest of large intestine, kidneys, gonads (pelvic viscera)

***Parasympathetic fibers are not distributed in all peripheral nerves. These DON’T go to sweat glands or blood vessels or arrector pilli muscle. Parasympathetic fibers have LIMITED distribution.