1 - Autonomic Nervous System Flashcards
(26 cards)
What is different regarding neural connections in the somatic vs autonomic nervous system?
Somatic = One neuron connection to muscle
Autonomic = Two neuron pwathway connects effection (preganglionic and postganglionic)
Two Types of Autonomic Neurons:
- Preganglionic
- Post Ganglionic
Preganglionic:
- First, cell body in CNS, axon passes out of CNS to synapse with dendrites/cell bodies of secondary neuron in PNS, myelinated (appears white) axon
Postganglionic:
- Cell body in autonomic ganglion, has axon travel to structure, unmyelinated (appears grey) axon
What are the three types of autonomic ganglia?
What are they based on?
Based on location in body
- Sympathetic Chain
- Prevertebral Ganglia
- Terminal Ganglia
Sympathetic Chain Ganglia
Located in sympathetic trunk, located adjacent to vertebral column
Extends form vertebra C1 to coccyx
Prevertebral (or preaortic) Ganglia
Located anterior to the lumbar vertebrae as well as abdominal aorta; most associated with the branches of abdominal aorta (celiac, superior and inferior mesenteric arteries)
Terminal Ganglia
Located within the wall of an organ or adjacent to the organ, parasympathetics
Sympathetics:
Preganglionic Neuronal Cell Body Location
Post Ganglionic Neuronal Cell Body Location
Function
Pre: Lateral horns of grey matter of spinal cord at thoracic and upper lumbar levels (T1-T12, L1-L3); Thoraco-Lumbar
Post: Located in sympathetic chain ganglia and preaortic (prevertebral)
Functions: Fight or Flight: Increase HR, dilate voluntary vessels/restrict skin/gut, EPINEPHRINE
Parasympathetics:
Preganglionic Cell Bodies
Post Ganglionic Cell Bodies
Functions
Pre - Cranial Nerve Nuclei 3, 7, 9, 10; gray matter of Sacra S2-S4; Cranio Sacral
Post - Located in terminal ganglia
Functions - Rest and Digest, Can cause opposite from sympathetics, exerts over short, limited region of body
Do organs usually receive sympathetics or parasympathetics?
Both para/symp fibers usually supply the same organ or structure
Usually act antagonistically
What three regions only receive supply from sympathetics?
- Sweat Glands
- Medulla of Adrenal Gland
- Arrector Pili Muscles (good pimples, erect hair)
Cranial Components of Parasympathetics:
Preganglionic Cell Bodies
Preganglionic Axons
Terminal Ganglia (Post Gang Bodies)
Postganglionic Axon
PreG Cell Bodies - Nucleus of Vagus Nerve (CN 10) in brainstem
Pre GAxons - Travel with vagus nerve descend neck; hitch ride with other structures (arteries, broncus, etc.)
Terminal Ganglia - Close / in Wall of targets
PostG Axon - Axon of neuron in terminal ganglion, short
What organs are targets for the Cranial Component of Parasympathetic Division?
What is their embryological origin?
- All thoracic Viscera
- Most of gut (as far as left colic flexure of large intestine)
- - -
Foregut / Midgut
Sacral Components of Parasympathetics:
Preganglionic Cell Bodies
Preganglionic Axons
Terminal Ganglia (Post Gang Bodies)
Postganglionic Axon
PreG Bodies - Gray matter of S2 - S4
PreG Axons - Leave spinal cord in ventral root, enter ventral ramus of S2 - S4; Ventral Rami of Sacral Spinal nerves enter Pelvic Cavity, form Pelvic Splanchnic Nerves, plexus on Arteries
Terminal Ganglia - Close to or in walls of targets
PostG Axon - Short
What organs are targets for the Sacral Comonent of Parasympathetics Division?
What is the embryological origin of these structures?
- Distal part of large bowel (beyond left colic flexure)
- Urinary Bladder
- - -
Hindgut
Sympathetics:
Preganglionic Cell Bodies
Preganglionic Fibers (Axons)
Exit and Rally?
PreG Bodies - Lateral horn T1-T12, L1-L3
Axons - Myelinated, exit the spinal cord via the ventral roots of spinal nerves and enter ventral rami of T1-T12, L1-L3
**Exit and Rally: Exit via White Ramus Communicans, rally to Sympathetics Chain Ganglion within Sympathetic Trunk
Sympathetics Trunk Location
Contents
Located lateral to vertebral column from C1 - Coccyx
Contains Preganglionic Sympathetic Fibers and Sympathetic Chain Ganglia located along its length
Sympathetics: Synapse with Chain Ganglia
Three Target Destinations
1 .Synapse with postganglioni neuronal cell body at same level
- Pass through chain ganglia (no synapse) and travel up or down sympathetic trunk to do #1 at a different level
- Cervical/Upper Thoracic Sympathetic Chain Ganglia can synapse and leave three cervical chain ganglia and upper thoracic sympathetic chain ganglia to go directly to structures in head, neck, thorax without entering a spinal nerve
What route does the postganglionic sympathetic neuron travel following synapse?
What does this junction join?
Gray Ramus Communicans
*Postganglionic axons are unmyelinated, hence gray name
Joins ventral ramus of a spinal nerve to travel to cutaneous structures or exits dorsal rami of spinal nerve to innervation structures of back
Sympathetics: Synapse with Pre-Aortic (Prevertebral) Ganglion
Where are ganglia located around?
Pass through chain ganglia (no synapse) and form Splanchnic Nerves (4x)
Emerge from from levels T5 - L2 to join Preaortic Ganglia in abdomen and pelvis
Located around roots of major aortic branches
Sympathetics: Synapse with Pre-Aortic (Prevertebral) Ganglion
Postganglionic Fibers
Fibers leave Preaortic Ganglion following synapse; and form Perivascular Plexus on branches of Aorta
Distributed to Abdominal-Pelvic Viscera
Memory Aid to Differentiate Splanchnic Nerves
Pelvic Splanchnic Nerves are
Parasympathetics,
Splanchnic Nerves are
Sympathetics
Which division of the ANS are pain afferents associated with?
Where are your cell bodies?
Sympathetics
Cell bodies of sensory neurons located in dorsal root ganglia of Spinal nerves T1 - T12, L1-L3
Where do the peripheral processes of sensory neurons (pain) leave the spinal nerve?
Where do they enter?
Ventral rami via White Rami Communicans
Enter sympathetic trunk
Contents of Splanchnic Nerves
- Preganglionic Sympathetic Fibers to Preaortic Ganglia
- Visceral Sensory Fibers from Organ Innervated
