Autonomic Nervous System Flashcards
What is the ANS in broad terms?
the efferent component of the visceral nervous system
aka the motor component of the visceral nervous system
visceral nervous system
lots of internal organs and smooth muscle!
What can the ANS be broken into?
parasympathetic and sympathetic nervous systems
sympathetic nervous systems
part of the ANS (visceral efferent / motor)
quick actions that use energy
ex: increase HR and vasoconstriction
parasympathetic nervous systems
part of the ANS (visceral efferent / motor)
preserve and store energy
ex: digestion and vasodilation
What do autonomic impulses travel along?
a chain of 2 neurons
a preganglionic and postganglionic neuron
where is a preganglionic neuron?
in the CNS (brain or spinal cord)
what neurotransmitter does a preganglionic neuron relase?
acetylcholine
what neurotrasmitter does postganglionic neuron release in sympathetic nervous system?
norepinephrine
EXCEPT when innervating sweat glands (acetylcholine)
what neurotrasmitter does postganglionic neuron release in parasympathetic nervous system?
acetylcholine
paravertebral ganglia
ganglia located lateral to spinal column
look like beads on a string
ONLY contain sympathetic cell bodies and fibers
prevertebral ganglia
found to close to or within walls of target organs
can contain parasympathetic and sympathetic cell bodies / fibers
how to preganglionic fibers leave the spinal cord?
through the vental root
what is the ventral root?
the motor root
when preganglionic (sympathetic) fibers leave the spinal cord through the ventral root, what do they enter neck?
the paravertebral ganglia
“beads on a string” lateral to spinal cord
are preganglionic fibers myelinated?
yes! this makes them leave the ventral ramus through a white communicating ramus
how do preganglionic fibers get to sympathetic trunk?
through the white communicating ramus
sympathetic trunk
beads on a string chain of sympathetic paravertebral column
are postganglionic fibers myelinated?
no! they leave the spinal nerve through grey ramus as a result
what is a ganglia?
clusters of nerve cell bodies
where are white rami found?
only T1-L2
because this is where the preganglionic fibers are and they are myelinated which makes them white
where are grey rami found?
found at all vertebral levels
because postganglionic sympathetic axons can ascend and descend down the sympathetic trunk
where are prevertebral ganglia?
closer to the target organ
adrenal gland
can accept preganglionic sympathetic fibers directly
can synapse here and release epinephrine / norepinephrine
preganglionic parasympathetic neurons
have a craniosacral distribution
more limited than the sympathetic neurons
where does most of the body wall innervation in the ANS come from?
sympathetic neurons
parasympathetic neurons have largely craniosacral distribution
vagus nerve
preganglionic parasympathetic neuron
