Lecture 10 - ANS Flashcards
Autonomic nervous system consists of: (4)
- Autonomic sensory neurons
- Integrating centers
- Autonomic motor neurons
- Enteric division
Autonomic sensory neurons are found where
In visceral organs & blood vessels
Integrating centers are found where
In the CNS
Autonomic motor neurons do what
Propagate from CNS to various effector tissues
Enteric division is what
Specialized network found within walls of the gastrointestinal (GI) tract
The visceral afferent and visceral efferent fibers travel ____
Together
Afferent component
autonomic reflexes and pain fibers
Efferent component
regulation of visceral function
2 motor neurons in series (myelinated + unmyelinated)
Visceral efferent pathway of the PNS (3)
Smooth muscles
Cardiac muscles
Glands
Smooth muscle effect
Contract/relax
Cardiac muscles effect
Increase or decrease rate/force of contraction
Glands effect
Increase or decrease secretions
ANS is organized into (3)
Nerves, ganglia, plexuses
Ganglia
Bundle of cell bodies
Plexuses
Bundle of ganglia
ANS is divided into 2 systems or divisions
- Sympathetic division
2. Parasympathetic division
Another name for sympathetic division + what nerves
Thoracolumbar
T1 to L2
Another name for parasympathetic division + what nerves
Craniosacral
CN III, CN VII, CN IX & CN X + S2, S3, S4
Explain the visceral efferent pathway in 3 steps
Neurons are mainly in lateral grey bodies with some anterior horn
They pass through the PREGANGLIONIC NEURON to synapse in the AUTONOMIC GANGLION
They then pass through to the POSTGANGLIONIC NEURON to the EFFECTOR
All the pre-ganglionic neurons release
Acetylcholine
The synapse of the preganglionic neurons (fibers) with another visceral efferent neuron occurs where
In the autonomic ganglia
There are 3 locations of ganglia
- Sympathetic trunk (chain)
- Prevertebral (collateral) ganglion
- Terminal (intramural) ganglion
Which location is only for parasympathetic division
Terminal (intramural) ganglion
Location of the sympathetic trunk
Closely on each side of the vertebral column, parallel to it
Location of the prevertebral (collateral) ganglion
Anterior to the large abdominal arteries
The prevertebral ganglion take their names from these arteries
Celiac ganglion (celiac artery) Superior and inferior mesenteric ganglion (artery)
Both the sympathetic trunk and the prevertebral ganglia receive their preganglionic fibers from the ________ division of the ANS
Thoracolumbar (sympathetic
Location of the terminal (intramural) ganglion
Very close to, or in the visceral effectors (smooth/cardiac muscle or glands)
The terminal ganglia receives preganglionic fibers directly from the ______ division of the ANS
Craniosacral/parasympathetic
T or F: all ganglia receive preganglionic neurons/fibers
TRUE
The preganglionic fibers have their cell bodies located where
In the lateral grey horns of the spinal cord
The autonomic efferent fibers leave by the ____ ____ of the spinal nerve accompanying the somatic efferent fibers
Ventral root
Sympathetic division - preganglionic fibers enter the sympathetic trunk/chain by way of the ____ ____ ____
White Rami Communicans
2 options to synapse for the preganglionic neurons of the sympathetic division
- synapse in the chain
2. go up or down to another level to synapse with the postganglionic neuron
T or F: one preganglionic neuron can have an influence up to 20 postganglionic neurons
TRUE
Sympathetic division - after the synapse, the postganglionic fibers enters the ___ ___ of the spinal nerve by way of the ___ ____ ___
Ventral rami
Grey Rami communicans
Where is synapse if not in the chain for sympathetic division
Pass right through it and later synapse in the prevertebral ganglia
These presynaptic nerves are found below the diagram
Splanchnic nerves
Celiac plexus (3)
Also known as the solar plexus
Is comprised of the paired celiac ganglia, superior mesenteric ganglia and other smaller ganglia
It lies in the anterior aorta at the origin of the celiac artery
All presynaptic neurons (parasympathetic) synapse in the ____ ____
Terminal ganglia
S-ANS: postganglionic fibers release ____
Called ____ fibers
Norepinephrine (noradrenaline)
Adrenergic
Norepinephrine will increase or decrease the activities of the organs
INCREASE
Prepares the individual for emergency situations - fight or fly
Sympathetic division
Effect of sympathetic on body (3)
Increase HR, aggression, adrenaline production
Increase blood flow to skeletal and cardiac muscles (vasodilation)
Non essential organs = vasoconstriction
PS-ANS: postganglionic fibers release ____
Called ____ fibers
Acetylcholine (ACH)
Cholinergic
Maintains the organs lever of activity to pressure (homeostasis - balance of bodily functions)
Parasympathetic division
In stressful situations, ____ divisions are dominant
Sympathetic
In non-stressful situations, ____ division is dominant
Parasympathetic
T or F: if the synapse occurs in the chain, it means the effector is below the diaphragm
FALSE, above the diaphragm
In the spinal cord, where do we find the cell bodies of motor neurons associated with the SNS?
Anterior grey horns
