Anatomy of the Autonomic Nervous System- Gilland Flashcards
the autonomic nervous system (ANS)
provides visceral motor control of smooth muscle, cardiac muscle, and glands
the anatomical and physiological system for visceral motor system
Efferent and afferent innervation of smooth and cardiac muscle and glands
ANS is organized into
sympathetic, parasympathetic, and enteric division
What are the peripheral nerve functional components?
afferent: input to the CNS= sensory
efferent: output from the CNS= motor
visceral: inner body
somatic: outer body
general found the spinal nerves and cranial nerves of the PNS
special: only found in cranial regions and branches of cranial nerves
Where does the somatopleure derive from?
it is derived from the
lateral mesoderm forms an outer and inner layer; the outer layer of the lateral mesoderm combines with the ectoderm to form the body wall and they get filled up with muscles derived from the somites
all of that is the somatopleure and its innervated is somatic
Visceral structure develop from the where?
splanchnic pleura; the inner layer of lateral mesoderm (the inner layer of the soleomic body cavity) it wraps around the endoderm of the gut tube and together that is the splanchnic pleura and so everything that innervates that is functionally part of the visceral nervous system
What is GSE?
- somatic and branchiomotor fibers innervate striated muscle that is derived from somites and head mesoderm
- both cranial and spinal nerves
- has to do with the body wall
- it’s afferent so it has to do with muscle derived from the somites
-GSE its motor innervation of skeletal or striated muscle
What is GSA?
sensory input coming from somatic structures: touch, temp, pain, itch from the skin
innervation of the outer surface of the body
What is GVE?
- this is equivalent to autonomic NS: sympathetic and parasympathetic
- autonomic efferent fibers innervate cardiac muscle, smooth muscles, and secretory cells in mucosa, dermis, and glands
- motor innervation to splanchnic pleura structures
- what characterizes the structures is compromised if they’re muscle they are not skeletal muscle
- they are either cardiac muscle or smooth muscle and the other ultimate target will be glands
- a lot of time people will talk about secretory modor??? and that is just GVE
- innervation of glandular structures
What is GVA?
- the sensory feedback coming back from whatever visceral structure it innervated
- every autonomic target will have afferent info coming back
- the afferent pathway follows back anatomically the efferent pathway
-sensory from visceral structures
how the gut abdomen???
What is SVA?
taste (gestation??? that is info coming from inside the oral and pharyngeal cavity and mucosa)
smell (olfactory)
??????
develop from the pharyngeal arches??????CT from neural crest NOT mesoderm
Paravertebral sympathetic ganglia are derived from embryonic neural crest cells
regular skeletal muscle CT
develop from paraaxial???
What is SVE?
branchiomotor muscles in the pharyngeal arches
What is SSA?
in eye and ear
WE WILL FOCUS ON GVE!!!
innervation of smooth muscle, cardiac muscle, and glands
what distinguish visceral motor innervation from somtic motor innervation as well as branchiomotor?
the motor neuron sends an axon out of ventral root to a striated muscle fiber and terminates at a NMJ with ACh
the visceral motor neuron is in the lateral horn and sends its axons out of ventral with target of autonomic ganglion
autonomic ganglion
visceral cluster of efferent neurons
What is the difference in neurotransmitters and myelination of fibers in the sympathetic and parasympathetic systems?
sympathetic:
- ACh and norepinephrine
- nicotinic receptor
parasympathetic:
- just ACh
- muscarinic receptor and nicotinic receptor
BOTH
- 2 neuron from CNS to target (preganglionic and postganglionic)
- preganglionic fibers are myelinated
- postganglionic fibers are NOT myelinated
Somatic vs. visceral efferent pathway
peripheral autonomic ganglion is the first synaptic target in the visceral efferent pathway
????
There is no parasympathetic out of the cervical, thoracic, or lumbar. Explain.
the parasympathetic portion of the autonomic nervous system is in the:
- brainstem ((CN III, VII, IX, X)
- sacral spinal cord (S2-S4)
AKA Cranio-Sacral outflow
What is the significance of T1-L2?
-sympathetic central neurons are found only in the thoracic and lumbar spinal cord between T1 and L2
-AKA thoracolumbar outflow
will project out of the peripheral to the CNS to target sympathetic ????
Visceral motor innervation is a TWO neuron path from CNS neurons to targets of smooth and cardiac muscles.
What is the only thing innervated by the preganglionic sympathetic neurons in the interomediolateral cell column of the lateral horn of spinal gray at levels from T1 to L2???????
-CNS neurons innervate peripheral autonomic ganglion cells. The ganglion cells innervate smooth muscle, cardiac muscle and glands.
- ALL the sympathetic ganglion cells in the body
- there are no other preganglionic sympathetic neurons other than those in the interomediolateral cell column
-parasympathetic nervous system includes preganglionic fibers that are axons of the central autonomic neurons, and postganglionic fibers that are axons of the autonomic ganglion cells
their axons are post-ganglion fibers
What are the functions for parasympathetic and sympathetic systems?
parasympathetic: rest and digest; parasympathetic efferents adapt the body for consumption and digestion of nutrients and for behaviors NOT associated with high levels of activity and metabolic demand
sympathetic: flight or fight (stress)
What is the DESCENDING pathway from hypothalamus for ventral motor control?
Cerebral control of visceral motor activity is mediated through descending projections of the hypothalamus, especially those of the…?
- paraventricular nucleus
- neurons in the paraventricular nucleus project to numerous CNS regions involved in regulation of visceral activities, including elements of the hypothalamic-pituitary-adrenal (HPA) axis and parasympathetic and sympathetic visceral motor nuclei of the brainstem and spinal cord
hypothalamospinal tract going to the ??????
How does the head and neck get sympathetic innervation?
cervical sympathetic trunk
cervical sympathetic chain ganglion
Since preganglionic neurons and white rami are found only between T1 and L2 levels, post ganglionic fibers must ascend or descend in the sympathetic trunk to reach parts of the body above and below these levels
Where are the preganglionic sympathetic coming from?
intermediolateral cell column in the lateral horn of spinal cord levels T1-L2
Paravertebral ganglion cells receive input from where?
only from preganglionic sympathetic neurons of T1-L2 spinal cord
-sympathetic trunk contains the paravertebral ganglion
Gray vs white communicating rami
- SYMPATHETIC fiber travel through these rami
- preganglionic sympathetic ganglion ENTER the sympathetic trunk by projecting fibers through white rami communicantes to synapse on cells in the paravertebral ganglia
-paravertebral ganglia LEAVE the sympathetic trunk by projecting fibers through the gray rami communicantes to join spinal nerves for distribution to blood vessels and dermis
chain ganglia
paravertebral ganglia
sympathetic ganglia of the sympathetic chain
????
gray ramus
path for postganglionic sympathetic fibers leaving the sympathetic trunk wanting to enter the spinal nerve
the fiber entering the do not necessarily go to the nearst segment to synapse
they can go up or down a couple of segments to synapse ???
Sympathetic cervical ganglion above T1 get their input from where?
input from white rami from spinal nerve lower than that
What are splanchnic nerves?
- are paired visceral nerves (nerves that contribute to the innervation of the internal organs), carrying fibers of the autonomic nervous system (visceral efferent fibers) as well as sensory fibers from the organs (visceral afferent fibers).
- axons of sympathetic ganglion can travel in splanchnic nerve to synapse on prevertebral ganglia AKA pre-aortic ganglia
- thoracic, lumbar, and sacral splanchnic nerves extend between the sympathetic trunks and preaortic ganglia/plexuses in the abdomen and pelvis
- carry preganglionic sympathetic fibers (and related sensory fibers) from the sympathetic trunks to the abdominal viscera
What are sympathetic cardiac nerves?
we DO NOT WANT TO SAY SPLANCTIC WITH THE NAME
what is the telling”? /
speed up and make each contraction stronger????
These ganglia are also called “preaortic”. They are named for the large arterial branches they surround, hence:
Celiac ganglion
Superior Mesenteric ganglion
Inferior mesenteric ganglion
ihinibit parastalic????
3 CN project to 4 paraysmptathetic ganlgion
- ciliary ganglion
- pteryogopalatine ganglion
- otic ganglion
- submandibular ganglion
- CN VII
- CN III
- CN IX
-vagus nerve: CN X (emerges from the medulla and targets is something else???
S2-S4
have white rami coming out from them?????
ciliary ganglion which will innervate two smooth muscles in the eye
????
input from the facial nerve??????
??????
carotid gland
the salivary gland for the upper part of your oral cavity
with input of CN IX
Dorsal Vagus Motor Nucleus
???
vagus nerve has its own sensory fibers
?????
vagus sensory neurons
?????nucleus of the solitary tract (NST)
somatomotor versus branchiomotor versus visceral motor
??????
General vs special
the distinction is between what goes on spinal nerve and what goes on in cranial nerves
General: found in both spinal and cranial regions of the CNS and PNS; the brain or spinal cord
Special: only found in cranial regions and is carried by the pathway for nerves that are special either sensory or motor or branches of cranial nerves
What is another name for GSE?
somatic motor (somatomotor)
What is another name for GSA?
somatic sensory, general sensory
What is another name for GVA?
visceral sensory
What is another name for SVA and SSA?
special sensory
What is another name for SVE?
branchiomotor
Somatic (and branchiomotor) motor fibers innervate striated muscle that is derived from somites and head _____;these fibers can be called general somatic efferent (GSE).
mesoderm
________–efferent fibers innervate cardiac muscle, smooth muscles, and secretory cells (in mucosa, dermis, and glands); these fibers can be called General Visceral Efferents (GVE).
Autonomic
Which muscles do somatic systems work with?
skeletal muscle
Which muscles do visceral systems work with?
smooth, cardiac glands
What is another name for the 1st pharyngeal arch?
mandibular arch
What is another name for the 2nd pharyngeal arch?
hyoid arch
What are the autonomic functions that are present in both PNS and SNS and distinct in each system?
BOTH SNS and PNS:
- cardiac functions
- pupillary reflexes
- cerebral vascular resistance
ONly SNS:
- most arterial smooth muscle (increased sympathetic activity results in acceleration and strengthening of heart beat)
- effectors in the skin such as arrector pili muscles and glands
- chromaffin cells in the adrenal medulla
ONly PNS:
- cilliary body which helps change lens shape
- lacrimal gland, salivary glands
Hypothalamospinal tract
- its nuclei in the CNS project axons to the preganglionic sympathetic visceral motor neurons in the interomediolateral cell column
- preganglionic neurons in the spinal cord in the interomediolateral cell column of T1-L2 innervate sympathetic ganglion cells and chromaffin cells in the adrenal medulla
What are the two main groups of sympathetic ganglia?
sympathetic trunk ganglia
- AKA sympathetic chain ganglia
- paravertebral ganglia
prevertebral ganglia
-AKA preaortic ganglia
Sympathetic, parasympathetic, and sensory fibers converge towards target organs in mixed (efferent/afferent) autonomic nerve plexuses. The plexuses contain what?
- pre and postganglionic sympathetic fibers (efferent) along with Dorsal Root Ganglion sensory fibers
- sympathetic ganglion cells
- preganglionic parasympathetic fibers, along with vagal sensory fibers
What are examples of somatic plexuses vs visceral plexuses?
Somatic plexuses:
- Cervical plexus
- Brachial plexus
- Lumbar plexus
- Sacral plexus
Visceral Plexuses:
- Vagus PS
- Cardiac plexus: contains sympathetic and parasympathetic (vagal) fibers as well as DRG and vagus sensory fibers)
- Esophageal plexus
- Thoracic aortic plexus
- Prevertebral plexus
- Pelvic plexus
Describe sympathetic innervation of the heart.
- postganglionic sympathetic fibers from cervical and thoracic paravertebral ganglia (sympathetic trunk) run in sympathetic cardiac nerves
- sympathetic cardiac nerves run from the sympathetic trunk to the cardiac plexus
autonomic control of cardiovascular function
-sensory signals pertaining to arterial pressure and blood oxygenation are relayed to the nucleus of solitary tract, which in turn organizes autonomic outflow via interneurons in the medullary reticular formation. This circuit provides negative feedback to visceral motor neurons that govern cardiovascular function
Parasympathetic preganglionic efferent fibers in cranial nerves III, VII, and IX innervate …
large parasympathetic ganglia in the head
-these ganglia innervate tear and salivary glands, smooth muscles in the eye and cerebral blood vessels
III: ciliary ganglion
VII (nervus intermedius): pterygopalatine ganglion
VII: submandibular ganglion
IX: otic ganglion
Vagus Nerve
- is mixed with both motor and sensory fibers
- vagus nerves (left and right) provides parasympathetic efferent innervation (GVE) and related GVA sensory innervation to almost all of the viscera of the neck, thorax, and abdomen
- visceromotor (GVE) fibers are mostly from the Dorsal Motor Nucleus of the Vagus target parasympathetic ganglia in the heart, lungs, and abdominal visera
- some fibers are from the Nucleus Ambiguus which is predominantly a branchiomotor nucleus (SVE) and mainly innervates striated muscles in the pharynx, larynx, and esophagus
- vagal afferent (GVA) fibers from the inferior vagal ganglion serve all of the organs that receive vagal efferents; located in the nodose ganglion and convey afferent input (EXCEPT PAIN) concerning distension of hollow organs, blood gases, pH to visceral afferent nucleus of the medulla, the Nucleus of Solitary Tract
About 75% of all parasympathetic nerve fibers are in what nerve?
vagus nerve
Sacral splanchnic nerves and pelvic splanchnic nerves carry what kind of fibers?
Sacral splanchnic nerves: Sympathetic fibers
pelvic splanchnic nerves: Parasympathetic fibers
The cell bodies of sensory neurons innervating visceral structures are located where?
DRG (spinal ganglia)
What is the general rule of thumb for visceral sensory innervation?
- the sensory (afferent) fibers to a particular visceral target area travel the same overall path as the efferent fibers that supply that area
- for example sensory innervation of a region of viscera will involve the DRG of the same spinal nerve whose white ramus and ventral root carried the preganglionic efferent fibers
- so to trace visceral afferent pathways, follow the visceral efferent pathway in reverse
Visceral pain and referred pain
IN CONTRAST to vagal sensory ganglia, DRG afferents to visceral organs do convey pain signals, mostly from stretch and pressure on internal organs
- because this visceral pain is not highly localized, it gets referred to somatic nerves as the visceral target
- for example, pain from an infected appendix is perceived by the patient as arising from somatic areas supplied by the same spinal nerve as the appendix, in this case the skin of the T10 dermatome
Why can denervated lengths of gut still perform peristalsis and secretory activity without input from sympathetic and parasympathetic systems (not as well though)?
enteric neural connections are sufficient to carry out basic GI activity without input from the CNS
