Anatomy Of Autonomic Nervous System

Question 1

Give the general characteristics of the ANS

Answer 1

Visceral-innervates 3 target tissues:
Smooth muscles(eg. GI tract, blood vessels)

Cardiac muscle (including conduction time)

Glands

Motor or efferent system: however sensory fibers travel along with autonomic nerve fibers

Question 2

What are the two major divisions of the ANS?

Answer 2

These divisions are different anatomically in transmitted used, effect on various organs
-sympathetic : controls organs in most times of stress

-parasympathetic: controls organs in times of rest

Most organs are innervated by both fibers- they counterbalance each other

Enteric- third component which is gut related

Question 3

What are the functions of the sympathetic ANS?

Answer 3

• fight, flight or fright mode
• catabolic system
• increased arterial pressure
• increased heart rate, force of contraction, cardiac output
• increased blood flow away from skin to skeletal muscles- cold, sweaty skin ( construct vessels to skin and gut/ dilate vessels to heart, muscles lungs)
• increased ventilation- dilation on airways - deep &. Rapid breathing
• pupillary dilation (greater field of vision)
• sweat glands

Question 4

What are the functions of the parasympathetic nervous system?

Answer 4

Rest and digest

• homeostatic or anabolic system
• decreased blood pressure
• decreased heart rate
• constriction of bronchial tree and decreased respiratory rates
• stimulation of gut activities - allows for digestion and waste removal
• warm skin

Pupillary constructor

Question 5

Describe somatic nervous system

Answer 5

One long, heavily myelinated axon extending from the CNS to the effector

Question 6

Describe autonomic motor neurons

Answer 6

Two neuron system

A lightly myelinated preganglionic neuron with the cell body in the CNS

An Unmyelinated postganglionic neuron with cell body in autonomic ganglion in the PNS

Question 7

What is one main distinction between SNS abs PSNS?

Answer 7

• location of preganglionic cell bodies
• location of post-ganglionic cell bodies

Parasympathetic ganglia in target organs

Sympathetic nervous system ganglia before target organs

Question 8

Where are the cell bodies of parasympathetic nervous system located?

Answer 8

Preganglionic

Parasympathetic outflow- cranial nerves III, VII, IX,X

Sacral spinal segments- S2-S4

Parasympathetic ganglia
Postganglionic parasympathetic cell bodies are found scattered near or in. The walls of target organs

Discrete parasympathetic ganglia are ONLY found in the head associated with the parasympathetic cranial nerves

Question 9

Where are the cell bodies of. sympathetic located?

Answer 9

Preganglionic
Sympathetic outflow- thoracolumbar-T1-L2

Postganglionic
Sympathetic ganglia
-sympathetic chain (trunk) ganglia(paravertebral ganglia )
-lateral aspect of vertebrae
-form superior cervical ganglion at the base of the skull
-To the ganglion impar at the level of the coccyx
-Associated with each spinal nerve: 1 pair per spinal nerve

Preaortic ganglia(prevertebral ganglia)
-located in the abdomen, associated with major branches of the abdominal aorta