Introduction To Autonomics Flashcards
Where are the cell bodies of the ANS found?
The lateral column of the gray matter
What is the structure of the ANS?
Has 2 neurons unlike somatic that has 1 except in adrenal medulla
What are the subdivisions of the ANS?
Sympathetic
Parasympathetic
What is the characteristic of the sympathetic?
Fight or flight system
Enters PNS only via thoracolumbar spinal nerves (T1-L2)
Long postganglionic fibers
Large ratio of postganglionic neurons to preganglionic fibers
Widespread influence
Diffuse phenomena
Emergency situations
What is the characteristic of the parasympathetic?
Enters PNS only via cranial nerves and sacral spinal nerves
Short postganglionic fibers
Small ratio of preganglionic fibers to postganglionic neurons
Localized influence
Associated with protection, rest and recuperation
Pupillary constrictions, decreased heart rate
Rest and digest system
What is the sympathetic division circuitry?
Preganglionic emerge from T1-L2 spinal cord and nerves
Preganglionic reach sympathetic trunk by passing through rootlets, roots, spinal nerves and white communicating rami
White rami only occur in association with spinal nerves T1-L2
What are the different paths of the preganglionic within the sympathetic trunk?
Synapse at the same spinal segment
Ascend and synapse in a higher or more cranial ganglion
Descend and synapse in a lower or more caudal ganglion
Emerge via thoracic and splanchnic nerves without a synapse
What are the types of postganglionic fibers of sympathetic division?
Perivascular-travel along arterial walls (carotid plexus)
Spinal-enter each spinal nerve through gray communicating rami, distribute to blood vessels, sweat glands piloerector muscles
Visceral-pass directly to viscera
What is the characteristic of the autonomic plexus ganglia?
Receive preganglionic fibers from splanchnic nerves
Send postganglionic fibers to viscera via abdominal and periarterial plexi
What are the postganglionic neurotransmitters?
All preganglionic nerves release acetylcholine
Postganglionic neurons of the parasympathetic release acetylcholine
Postganglionic neurons of the sympathetic release norepinephrine to various organs, acetylcholine to sweat glands, and epinephrine for the adrenal medulla
What is the characteristic of the enteric nervous system?
Formed by 2 network of ganglia with neurons the myenteric plexus and the submucous plexus.
Can be modulated by sympathetic and parasympathetic
Parasympathetic is more of a stimulator
Sympathetic is more of an inhibitor
What is the characteristics of an autonomic afferents?
Impulse arise from viscera and blood vessels
Most visceral impulses do not reach consciousness
If awareness is present the localized sensations are vague and poor
Visceral organs are insensitive to ordinary mechanical and thermal stimuli
Viscera sensitive to excessive stretch, intense spasmodic contractions, decreased blood supply
Pain which can be true or referred
What is the basis for referred pain?
As the sensory nerves get to the dorsal horn , they share the locations which other nerves
The signals can be sent too other area causing referred pain
