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Ch. 14 The Autonomic Nervous System
Hoehn - Marieb Human Anatomy & Physiology, 12th edition
Hoehn, Haynes, Abbott12th EditionMarieb Human Anatomy & PhysiologyISBN: 9780138242732Not the one you use?Change textbook
All textbooksHoehn, Haynes, Abbott 12th EditionCh. 14 The Autonomic Nervous SystemProblem 3
Chapter 14, Problem 3

The white rami communicantes contain what kind of fibers?
a. Preganglionic parasympathetic
b. Postganglionic parasympathetic
c. Preganglionic sympathetic
d. Postganglionic sympathetic

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1
Step 1: Understand the role of rami communicantes in the autonomic nervous system. They are nerve fibers that connect the spinal nerves to the sympathetic trunk (chain ganglia).
Step 2: Recall that there are two types of rami communicantes: white rami communicantes and gray rami communicantes. Each carries different types of fibers.
Step 3: Know that white rami communicantes carry myelinated preganglionic sympathetic fibers from the spinal cord to the sympathetic ganglia. These fibers are responsible for transmitting signals from the central nervous system to the sympathetic ganglia.
Step 4: Contrast this with gray rami communicantes, which carry unmyelinated postganglionic sympathetic fibers from the sympathetic ganglia back to the spinal nerves to reach target organs.
Step 5: Based on this understanding, identify that the white rami communicantes contain preganglionic sympathetic fibers.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

White Rami Communicantes

White rami communicantes are nerve fibers that connect the spinal nerves to the sympathetic trunk. They carry myelinated preganglionic sympathetic fibers from the spinal cord to the sympathetic ganglia, enabling the transmission of signals in the sympathetic nervous system.
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Preganglionic vs. Postganglionic Fibers

Preganglionic fibers originate in the central nervous system and synapse in autonomic ganglia, while postganglionic fibers extend from these ganglia to target organs. Preganglionic fibers are typically myelinated, allowing faster signal conduction.
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Sympathetic vs. Parasympathetic Fibers

The autonomic nervous system has two divisions: sympathetic and parasympathetic. Sympathetic fibers prepare the body for 'fight or flight' responses, while parasympathetic fibers support 'rest and digest' functions. White rami communicantes specifically carry sympathetic fibers.
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Related Practice
Textbook Question

Collateral sympathetic ganglia are involved with innervating

a. abdominal organs

b. thoracic organs

c. head

d. arrector pili

e. all of these

Textbook Question

Which ANS fibers release acetylcholine? Which release norepinephrine?

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Textbook Question

All of the following characterize the ANS except

a. A two-neuron efferent chain

b. Presence of neuron cell bodies in the CNS

c. Presence of neuron cell bodies in the ganglia

d. Innervation of skeletal muscles

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Textbook Question

Where are the cell bodies of visceral sensory neurons?

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Textbook Question

Relate each of the following terms or phrases to either the sympathetic (S) or parasympathetic (P) division of the autonomic nervous system: 

______ (1) Short preganglionic, long postganglionic fibers 

______ (2) Intramural ganglia 

______ (3) Craniosacral part 

______ (4) Adrenergic fibers 

______ (5) Cervical ganglia 

______ (6) Otic and ciliary ganglia

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