What does the autonomic nervous system (ANS) regulate?
The ANS regulates homeostasis and controls internal organs' activity.
What are the main divisions of the ANS?
The sympathetic and parasympathetic divisions.
Where are the GVE motor neurons located?
In the spinal cord and brainstem.
How does the ANS work with the endocrine system?
The ANS regulates organ function alongside the endocrine system.
What is the role of the ANS in glandular control?
It regulates secretory activity in both large and small glands.
The autonomic nervous system controls smooth muscle in the body, including smooth muscle of _______, _______, and glands.
The autonomic nervous system controls smooth muscle in the body, including smooth muscle of blood vessels, the gut, and glands.
What types of organs does the ANS regulate more heavily?
Organs like the heart are highly regulated by the ANS.
Which organ receives only minor regulation from the ANS?
The kidneys mainly function through hormonal control, with minor ANS input.
What are sensory ganglia?
They house sensory neuron cell bodies in the ANS.
What is a synonym for sympathetic chain ganglia?
Paravertebral ganglia.
What is the function of GVE neurons in the sympathetic pathways?
They transmit signals from the CNS to target organs.
Which cranial nerve is involved in parasympathetic pathways to thoracic and abdominal organs?
Cranial Nerve X (Vagus Nerve).
What is the function of the smooth muscle in the gastrointestinal tract?
It aids in the movement of food and digestion.
How does the ANS affect heart rate?
It regulates heart rate and blood pressure.
What type of information does the ANS process?
Sensory information from the peripheral nervous system.
The ANS primarily uses two types of neurons in the efferent pathway: _______ and _______.
The ANS primarily uses two types of neurons in the efferent pathway: pre-ganglionic neurons and post-ganglionic neurons.
What is a synonym for preaortic ganglia?
Collateral ganglia.
What types of muscle does the ANS regulate?
Smooth muscle and glands.
The sympathetic pathways can be described as those that transmit signals to the _______, and to _______.
The sympathetic pathways can be described as those that transmit signals to the body wall and limbs, and to thoracic, abdominal, and pelvic organs.
What do older textbooks classify the ANS as?
Only the GVE neurons and their axons.
What do modern neurobiological descriptions include in the ANS?
GVA sensory neurons and their connections in the CNS.
What types of sensory information do GVA neurons carry?
From which regions does control over the ANS come?
Mainly from the brainstem and spinal cord.
Which higher brain regions help regulate the motorneurons of the ANS?
How can hormones affect the ANS?
Certain hormones detected mainly in the hypothalamus can regulate activity of some output of the ANS.
What is the pupillary light reflex mediated by?
Autonomic GVE axons.
What can the baroreflex and vaso-vagal responses affect?
They can severely affect patients' ability to function safely in daily activities.
Why is excessive or lack of sweating clinically significant?
It can provide insight into parts of the CNS that are affected.
How do the sympathetic and parasympathetic systems function?
They work together to regulate aspects of visceral function, usually in an antagonistic manner.
What is one way to view the balance between the sympathetic and parasympathetic systems?
As a push/pull or yin/yang manner regulating homeostasis.
What is the output of the sympathetic nervous system often described as?
The 'fight or flight' response.
When is the sympathetic nervous system most active?
During increased activity of the body or in response to stress.
What are effects of sympathetic stimulation?
What is the output of the parasympathetic nervous system referred to as?
The 'rest and digest' response.
When is the parasympathetic nervous system most active?
When activity and stress levels are low.
What are effects of parasympathetic stimulation?
The sympathetic nervous system is responsible for the _______ response.
The sympathetic nervous system is responsible for the 'fight or flight' response.
The parasympathetic nervous system is known as the _______ response.
The parasympathetic nervous system is known as the 'rest and digest' response.
How do the sympathetic and parasympathetic nervous systems interact?
Each system regulates the other to dampen down the other's activity.
What is an example of synergy between sympathetic and parasympathetic systems?
The sexual response, which requires both types of stimulation.
What can happen when the parasympathetic system is activated while studying?
Digestion may be impaired because the sympathetic system is activated as well.
How long might it take for homeostasis to be restored between the two systems?
It may take a while.
What is the enteric nervous system?
A separate system of sensory and motor neurons in the gut wall.
What role does the enteric nervous system play?
It helps regulate numerous digestive functions.
Is the enteric nervous system considered part of the ANS?
Some authors include it as part of the ANS, while others categorize it separately.
What are the main components of the efferent autonomic pathways?
Where do efferent pathways originate?
How many neurons are there in the efferent autonomic pathway chain?
There are two neurons in the chain.
What is a ganglion?
A collection of neuron cell bodies in the PNS with a common function.
What structures do GVE pathways typically target?
What type of axons do sympathetic efferent neurons follow?
They follow spinal nerves and their branches.
Where do parasympathetic efferent axons emerge from?
They emerge from the brainstem.
What type of information does GVA axons convey?
Where is the neuron cell body of sensory GVA axons typically located?
In a DRG or related sensory ganglia.
What is carried by cranial nerves?
They carry other types of afferent and efferent axons.
The efferent autonomic pathways consist of two neurons: the first neuron cell body is in the CNS, and its axon travels in the PNS to synapse onto a neuron cell body in the PNS, while the second axon stays in the PNS to reach the _______.
The efferent autonomic pathways consist of two neurons: the first neuron cell body is in the CNS, and its axon travels in the PNS to synapse onto a neuron cell body in the PNS, while the second axon stays in the PNS to reach the target organ.
Efferent autonomic pathways target structures such as glands, smooth muscle associated with the gut, and even the _______.
Efferent autonomic pathways target structures such as glands, smooth muscle associated with the gut, and even the smooth muscle of blood vessels.
Sensory axons from visceral structures, known as _______, travel along the same route as GVE efferent axons back to the CNS.
Sensory axons from visceral structures, known as GVA fibers, travel along the same route as GVE efferent axons back to the CNS.
What is a nucleus in the CNS?
A nucleus is a collection of neuron cell bodies with a common function and location in the CNS.
What are sensory ganglia?
Sensory ganglia, such as the DRG, are collections of neuron cell bodies, but not the focus here.
What is the function of ganglia in the ANS?
In the ANS, ganglia are where GVE efferent neurons synapse onto second GVE neurons.
What are preganglionic neurons?
Preganglionic neurons are the first GVE neurons located in the CNS.
Where are sympathetic GVE neurons located?
Sympathetic GVE neurons are located in the thoracic and lumbar spinal cord.
What is the thoracolumbar system?
The thoracolumbar system refers to the sympathetic efferent system.
Where are parasympathetic GVE neurons located?
Parasympathetic GVE neurons are located in cranial nerve nuclei or the sacral spinal cord.
What is the craniosacral system?
The craniosacral system refers to the parasympathetic efferent system.
What do preganglionic neurons do?
Preganglionic neurons send their axons TO a GANGLION.
What do postganglionic neurons do?
Postganglionic neurons send their axons AWAY FROM a GANGLION.
What are sympathetic chain ganglia?
Sympathetic chain ganglia, or paravertebral ganglia, are paired structures outside the vertebral column.
Where are sympathetic chain ganglia located?
They are located deep in the neck, thorax, and abdomen, just lateral to the vertebrae.
What do postganglionic neurons of the sympathetic chain project to?
They project axons out to the skin and blood vessels of the skin and skeletal muscle.
What are preaortic ganglia?
Preaortic ganglia, or prevertebral ganglia, are unpaired structures located deep in the abdominal cavity.
Where are preaortic ganglia located?
They are located immediately anterior to the abdominal aorta.
What are the three main ganglia in the abdomen?
Celiac ganglion, superior mesenteric ganglion, and inferior mesenteric ganglion.
What are celiac and mesenteric ganglia named for?
They are named for the blood vessels they are located near.
What are postganglionic neurons?
Postganglionic neurons are located in ganglia in the PNS.
Where are sympathetic ganglia located?
Sympathetic ganglia exist mainly for postganglionic neurons to viscera of the pelvis, embedded within the plexus of nerves associated with pelvic organs.
In which areas are parasympathetic ganglia located?
Parasympathetic GVE ganglia are located in the head, thorax, abdomen, and lower abdomen/pelvis.
What does the Ciliary Ganglion control?
The Ciliary Ganglion controls smooth muscle within the eyeball for pupil constriction and lens shape adjustment.
What is the function of the Pterygopalatine Ganglion?
The Pterygopalatine Ganglion controls the secretion of tear fluid and secretion from nasal/oral mucosa.
What does the Submandibular Ganglion regulate?
The Submandibular Ganglion regulates the secretion of saliva from glands in the mouth.
What is the role of the Otic Ganglion?
The Otic Ganglion controls the secretion of saliva from the parotid gland.
Where are unnamed parasympathetic ganglia located?
Numerous small unnamed ganglia are located in the walls of thoracic and abdominal organs.
How are ganglia in the lower abdomen/pelvis organized?
Ganglia in lower abdomen/pelvis are also embedded within the wall of each organ.
Why are postganglionic axons short in the parasympathetic system?
Postganglionic axons are short because the neurons in the ganglia are very close to their target organs.
How do sympathetic pathways differ from parasympathetic ones?
Sympathetic pathways often have relatively long postganglionic axons due to ganglia being far from target organs.
Where are preganglionic sympathetic neurons located?
Preganglionic sympathetic neurons are located in the lateral horn of the spinal cord from T1 to L2.
What is significant about the sympathetic chain of ganglia?
The sympathetic chain of ganglia is in the PNS, extends above T1 into cervical regions, and below L2 to sacral/coccygeal regions.
Where is the postganglionic neuron cell body located for the pathway to the body wall?
The postganglionic neuron cell body is located directly in the sympathetic chain.
What are the target organs for the pathway to the body wall?
In which spinal cord level are preganglionic neuron cell bodies for the pathway to the body wall located?
Preganglionic neuron cell bodies are located in the lateral horn at T4 spinal cord level.
How does the preganglionic axon reach the T4 sympathetic ganglion?
What does the postganglionic axon do after leaving the ganglion?
The postganglionic axon exits via a grey ramus communicante and rejoins the spinal nerve.
What is the dermatome level for the target organs of the T4 spinal cord?
Target organs are located at the T4 dermatome level.
Where is the synapse for the pathway to the limbs located?
The synapse is in the sympathetic chain, possibly above T1 or below L2.
What are the target organs for the pathway to the limbs?
What spinal nerves provide somatic innervation to the upper limbs?
Somatic innervation to upper limbs is from lower cervical to T1 spinal nerves.
What spinal nerves provide somatic innervation to the lower limbs?
Somatic innervation to lower limbs is from lumbar and sacral spinal nerves.
How do preganglionic axons for the limbs exit the sympathetic chain?
Preganglionic axons either ascend for upper limb or descend for lower limb sympathetic chain ganglia.
What is one example of the preganglionic neuron cell body for the upper limb pathway?
Located in the lateral horn of T2 spinal cord level.
How does the preganglionic axon for the upper limb start its path?
Where does the preganglionic axon ascend for upper limb innervation?
The axon ascends to the middle cervical ganglion.
Where do preganglionic axons synapse onto postganglionic neurons?
In the ganglion.
What structure does the postganglionic axon leave via?
The grey ramus communicante.
What project does the postganglionic axon follow to reach the target organ?
The ventral ramus and the brachial plexus.
From where do preganglionic axons originate in the cervical spinal cord?
Upper thoracic spinal cord levels.
Where are preganglionic neurons located for the lower limb?
Lower thoracic and L1/L2 lateral horn.
What happens to preganglionic axons once they reach the sympathetic chain?
They descend to lower lumbar and sacral sympathetic chain ganglia.
Where do the preganglionic neurons of the head/neck structures synapse?
In the superior cervical ganglion (SCG).
What organs are the target for the head/neck pathway?
Specialized smooth muscles and glands of the head.
What is the location of the SCG?
Just inferior to the base of the skull.
What allows postganglionic axons to reach target organs?
They follow blood vessels and sometimes nerves.
Where do postganglionic neuron cell bodies for thoracic organs reside?
In the cervical or upper thoracic sympathetic chain ganglia.
What is the main target of the thoracic pathway?
The heart and lungs.
Where do preganglionic neurons for abdominal organs synapse?
In preaortic (prevertebral) ganglia.
Which organs are mainly targeted by the abdominal pathway?
Gut, liver, pancreas, and kidneys.
Where are the preganglionic neuron cell bodies located?
In the lateral horn of the T5-T12 spinal cord.
Do preganglionic axons synapse in the sympathetic chain?
No, they leave the chain medially.
How do preganglionic axons reach the preaortic/prevertebral ganglia?
They leave the chain as splanchnic nerves.
Where do postganglionic neurons from the preaortic ganglia send their axons?
Along blood vessels to the target organs.
How are the sympathetic pathways to pelvic organs described?
Somewhat similar to the pathways for abdominal organs, but slightly different.
How many neurons compose the sensory pathways following sympathetic pathways?
A single neuron with a long axon from the sensory receptor to the CNS.
Where is the cell body of the sensory neuron located?
In a dorsal root ganglion (DRG).
Do sensory ganglia have synapses?
No, there are no synapses in sensory ganglia.
What general rule applies to pain from internal organs?
It follows sympathetic routes to the CNS.
How do pain axons from organs return to spinal nerves?
They travel back through splanchnic and sympathetic nerves without synapsing.
Where do pain pathways from viscera mix once in the CNS?
With somatic pain pathways in the spinal cord.
What causes referred pain from internal organs?
Visceral pain pathways mix with somatic pain pathways.
Where are the cell bodies for minor GVA axons located?
In DRG at the T1 to L2 spinal cord/spinal nerve level.
What type of information do GVA axons/neurons carry?
Physiological information from glands and vessels innervated by sympathetic efferent axons.
What minor axons are present in pathways to somatic structures?
Minor GVA axons.
What is the main role of the Vagus Nerve (CN X) in the parasympathetic pathways?
It primarily innervates internal organs in the thorax and abdomen.
What is the craniosacral division of the ANS?
It refers to the parasympathetic division that originates in the brain and sacral spinal cord.
Which cranial nerves are associated with preganglionic parasympathetic nuclei in the brainstem?
Cranial nerves III, VII, IX, and X.
What do the postganglionic axons of cranial nerves III, VII, and IX do?
They leave the ganglion and follow branches to reach the target organ.
What is the effect of parasympathetics on target glands?
They increase secretion, making the glands more active.
What is a primary target of the parasympathetic pathways in the head?
Specialized glands and smooth muscles of the eye.
Where are the preganglionic parasympathetic neuron cell bodies of CN III located?
In the Edinger-Westphal Nucleus of the midbrain.
What happens when the parasympathetic system affects the smooth muscle in the eye?
It adjusts for near vision.
Cranial nerves _______, _______, _______, and _______ are connected to preganglionic parasympathetic nuclei in the brainstem.
Cranial nerves III, VII, IX, and X are connected to preganglionic parasympathetic nuclei in the brainstem.
The _______ mainly targets internal organs in the thorax and abdomen as part of the parasympathetic pathways.
The Vagus Nerve mainly targets internal organs in the thorax and abdomen as part of the parasympathetic pathways.
The _______ in the head contain postganglionic neurons associated with the parasympathetic pathway.
The parasympathetic ganglia in the head contain postganglionic neurons associated with the parasympathetic pathway.
What is the primary function of the parasympathetic division?
Regulate rest and digest functions
Increase heart rate
Stimulate sweat glands
Prepare body for fight or flight
What is the primary function of the parasympathetic division?
Regulate rest and digest functions
Increase heart rate
Stimulate sweat glands
Prepare body for fight or flight
Which cranial nerve does NOT contribute to parasympathetic pathways?
CN VII
CN III
CN X
CN IX
Which cranial nerve does NOT contribute to parasympathetic pathways?
CN VII
CN III
CN X
CN IX
Where are postganglionic neuron cell bodies located for the pupil constriction?
In the Ciliary Ganglion (just behind the eyeball).
What are the target organs of postganglionic neurons from the Ciliary Ganglion?
Where are preganglionic parasympathetic neuron cell bodies for CN VII located?
In the Superior Salivatory Nucleus of the pons.
What ganglia do axons from CN VII travel to?
What are the target organs of the Pterygopalatine Ganglion?
What are the target organs of the Submandibular Ganglion?
Where are preganglionic parasympathetic neuron cell bodies for CN IX located?
In the Inferior Salivatory Nucleus of the pons.
What is the target organ of postganglionic neurons from the Otic Ganglion?
Parotid salivary gland outside the mouth (below the ear).
Where are preganglionic parasympathetic neurons for thoracic and abdominal organs located?
In the Dorsal Motor Nucleus of the Vagus (DMN of X).
What happens to the preganglionic axons of CN X?
They descend through the skull and neck to the thorax.
What occurs to CN X in the abdomen?
Branches follow arteries to gut and abdominal organs.
Where do preganglionic axons terminate?
On small, unnamed ganglia within the wall of each organ.
What is the role of parasympathetic stimulation?
Helps the body 'rest and digest'.
Where are preganglionic parasympathetic neurons for distal gut located?
In the sacral spinal cord at levels S2, S3, & S4.
What is the name of the nucleus in the sacral cord?
It is called the sacral parasympathetic nucleus.
How do the preganglionic axons leave the CNS in the sacral region?
They leave in ventral roots and follow spinal nerves.
What happens to the axons after following spinal nerves?
They separate as distinct parasympathetic nerves to target organs.
What do small unnamed ganglia near or within the wall of each organ contain?
Where do postganglionic axons synapse?
What is not necessary when tracing sensory (GVA) axons from glands/smooth muscle of the head?
Where do GVA sensory axons from thoracic and most abdominal organs follow back to?
What is located at the base of the skull related to the vagus nerve?
What is directly analogous to a dorsal root ganglion (DRG)?
Where do no synapses occur?
Where do sensory axons synapse after continuing into the CNS?
What is the name of the nucleus in the medulla where sensory axons synapse?
What type of information do GSA neurons carry?
What is not carried by the vagus nerve?
From where do GVA sensory axons of the distal gut follow back?
Where are neuron cell bodies located for GVA axons from the distal gut?
Where do axons of GVA sensory neurons continue into?
What does the autonomic nervous system (ANS) regulate?
The ANS regulates homeostasis and controls internal organs' activity.
How does the ANS work with the endocrine system?
The ANS regulates organ function alongside the endocrine system.
What is the role of the ANS in glandular control?
It regulates secretory activity in both large and small glands.
The autonomic nervous system controls smooth muscle in the body, including smooth muscle of blood vessels, the gut, and glands.
What types of organs does the ANS regulate more heavily?
Organs like the heart are highly regulated by the ANS.
Which organ receives only minor regulation from the ANS?
The kidneys mainly function through hormonal control, with minor ANS input.
What is the function of GVE neurons in the sympathetic pathways?
They transmit signals from the CNS to target organs.
Which cranial nerve is involved in parasympathetic pathways to thoracic and abdominal organs?
Cranial Nerve X (Vagus Nerve).
What is the function of the smooth muscle in the gastrointestinal tract?
It aids in the movement of food and digestion.
What type of information does the ANS process?
Sensory information from the peripheral nervous system.
The ANS primarily uses two types of neurons in the efferent pathway: pre-ganglionic neurons and post-ganglionic neurons.
The sympathetic pathways can be described as those that transmit signals to the body wall and limbs, and to thoracic, abdominal, and pelvic organs.
What do modern neurobiological descriptions include in the ANS?
GVA sensory neurons and their connections in the CNS.
What types of sensory information do GVA neurons carry?
Which higher brain regions help regulate the motorneurons of the ANS?
How can hormones affect the ANS?
Certain hormones detected mainly in the hypothalamus can regulate activity of some output of the ANS.
What can the baroreflex and vaso-vagal responses affect?
They can severely affect patients' ability to function safely in daily activities.
Why is excessive or lack of sweating clinically significant?
It can provide insight into parts of the CNS that are affected.
How do the sympathetic and parasympathetic systems function?
They work together to regulate aspects of visceral function, usually in an antagonistic manner.
What is one way to view the balance between the sympathetic and parasympathetic systems?
As a push/pull or yin/yang manner regulating homeostasis.
What is the output of the sympathetic nervous system often described as?
The 'fight or flight' response.
When is the sympathetic nervous system most active?
During increased activity of the body or in response to stress.
What are effects of sympathetic stimulation?
What is the output of the parasympathetic nervous system referred to as?
The 'rest and digest' response.
What are effects of parasympathetic stimulation?
How do the sympathetic and parasympathetic nervous systems interact?
Each system regulates the other to dampen down the other's activity.
What is an example of synergy between sympathetic and parasympathetic systems?
The sexual response, which requires both types of stimulation.
What can happen when the parasympathetic system is activated while studying?
Digestion may be impaired because the sympathetic system is activated as well.
Is the enteric nervous system considered part of the ANS?
Some authors include it as part of the ANS, while others categorize it separately.
What are the main components of the efferent autonomic pathways?
How many neurons are there in the efferent autonomic pathway chain?
There are two neurons in the chain.
What type of axons do sympathetic efferent neurons follow?
They follow spinal nerves and their branches.
What type of information does GVA axons convey?
Where is the neuron cell body of sensory GVA axons typically located?
In a DRG or related sensory ganglia.
The efferent autonomic pathways consist of two neurons: the first neuron cell body is in the CNS, and its axon travels in the PNS to synapse onto a neuron cell body in the PNS, while the second axon stays in the PNS to reach the target organ.
Efferent autonomic pathways target structures such as glands, smooth muscle associated with the gut, and even the smooth muscle of blood vessels.
Sensory axons from visceral structures, known as GVA fibers, travel along the same route as GVE efferent axons back to the CNS.
What is a nucleus in the CNS?
A nucleus is a collection of neuron cell bodies with a common function and location in the CNS.
What are sensory ganglia?
Sensory ganglia, such as the DRG, are collections of neuron cell bodies, but not the focus here.
What is the function of ganglia in the ANS?
In the ANS, ganglia are where GVE efferent neurons synapse onto second GVE neurons.
Where are sympathetic GVE neurons located?
Sympathetic GVE neurons are located in the thoracic and lumbar spinal cord.
What is the thoracolumbar system?
The thoracolumbar system refers to the sympathetic efferent system.
Where are parasympathetic GVE neurons located?
Parasympathetic GVE neurons are located in cranial nerve nuclei or the sacral spinal cord.
What is the craniosacral system?
The craniosacral system refers to the parasympathetic efferent system.
What are sympathetic chain ganglia?
Sympathetic chain ganglia, or paravertebral ganglia, are paired structures outside the vertebral column.
Where are sympathetic chain ganglia located?
They are located deep in the neck, thorax, and abdomen, just lateral to the vertebrae.
What do postganglionic neurons of the sympathetic chain project to?
They project axons out to the skin and blood vessels of the skin and skeletal muscle.
What are preaortic ganglia?
Preaortic ganglia, or prevertebral ganglia, are unpaired structures located deep in the abdominal cavity.
What are the three main ganglia in the abdomen?
Celiac ganglion, superior mesenteric ganglion, and inferior mesenteric ganglion.
What are celiac and mesenteric ganglia named for?
They are named for the blood vessels they are located near.
Where are sympathetic ganglia located?
Sympathetic ganglia exist mainly for postganglionic neurons to viscera of the pelvis, embedded within the plexus of nerves associated with pelvic organs.
In which areas are parasympathetic ganglia located?
Parasympathetic GVE ganglia are located in the head, thorax, abdomen, and lower abdomen/pelvis.
What does the Ciliary Ganglion control?
The Ciliary Ganglion controls smooth muscle within the eyeball for pupil constriction and lens shape adjustment.
What is the function of the Pterygopalatine Ganglion?
The Pterygopalatine Ganglion controls the secretion of tear fluid and secretion from nasal/oral mucosa.
What does the Submandibular Ganglion regulate?
The Submandibular Ganglion regulates the secretion of saliva from glands in the mouth.
What is the role of the Otic Ganglion?
The Otic Ganglion controls the secretion of saliva from the parotid gland.
Where are unnamed parasympathetic ganglia located?
Numerous small unnamed ganglia are located in the walls of thoracic and abdominal organs.
How are ganglia in the lower abdomen/pelvis organized?
Ganglia in lower abdomen/pelvis are also embedded within the wall of each organ.
Why are postganglionic axons short in the parasympathetic system?
Postganglionic axons are short because the neurons in the ganglia are very close to their target organs.
How do sympathetic pathways differ from parasympathetic ones?
Sympathetic pathways often have relatively long postganglionic axons due to ganglia being far from target organs.
Where are preganglionic sympathetic neurons located?
Preganglionic sympathetic neurons are located in the lateral horn of the spinal cord from T1 to L2.
What is significant about the sympathetic chain of ganglia?
The sympathetic chain of ganglia is in the PNS, extends above T1 into cervical regions, and below L2 to sacral/coccygeal regions.
Where is the postganglionic neuron cell body located for the pathway to the body wall?
The postganglionic neuron cell body is located directly in the sympathetic chain.
What are the target organs for the pathway to the body wall?
In which spinal cord level are preganglionic neuron cell bodies for the pathway to the body wall located?
Preganglionic neuron cell bodies are located in the lateral horn at T4 spinal cord level.
How does the preganglionic axon reach the T4 sympathetic ganglion?
What does the postganglionic axon do after leaving the ganglion?
The postganglionic axon exits via a grey ramus communicante and rejoins the spinal nerve.
What is the dermatome level for the target organs of the T4 spinal cord?
Target organs are located at the T4 dermatome level.
Where is the synapse for the pathway to the limbs located?
The synapse is in the sympathetic chain, possibly above T1 or below L2.
What are the target organs for the pathway to the limbs?
What spinal nerves provide somatic innervation to the upper limbs?
Somatic innervation to upper limbs is from lower cervical to T1 spinal nerves.
What spinal nerves provide somatic innervation to the lower limbs?
Somatic innervation to lower limbs is from lumbar and sacral spinal nerves.
How do preganglionic axons for the limbs exit the sympathetic chain?
Preganglionic axons either ascend for upper limb or descend for lower limb sympathetic chain ganglia.
What is one example of the preganglionic neuron cell body for the upper limb pathway?
Located in the lateral horn of T2 spinal cord level.
How does the preganglionic axon for the upper limb start its path?
Where does the preganglionic axon ascend for upper limb innervation?
The axon ascends to the middle cervical ganglion.
What project does the postganglionic axon follow to reach the target organ?
The ventral ramus and the brachial plexus.
From where do preganglionic axons originate in the cervical spinal cord?
Upper thoracic spinal cord levels.
What happens to preganglionic axons once they reach the sympathetic chain?
They descend to lower lumbar and sacral sympathetic chain ganglia.
Where do the preganglionic neurons of the head/neck structures synapse?
In the superior cervical ganglion (SCG).
What organs are the target for the head/neck pathway?
Specialized smooth muscles and glands of the head.
What allows postganglionic axons to reach target organs?
They follow blood vessels and sometimes nerves.
Where do postganglionic neuron cell bodies for thoracic organs reside?
In the cervical or upper thoracic sympathetic chain ganglia.
Where are the preganglionic neuron cell bodies located?
In the lateral horn of the T5-T12 spinal cord.
How do preganglionic axons reach the preaortic/prevertebral ganglia?
They leave the chain as splanchnic nerves.
Where do postganglionic neurons from the preaortic ganglia send their axons?
Along blood vessels to the target organs.
How are the sympathetic pathways to pelvic organs described?
Somewhat similar to the pathways for abdominal organs, but slightly different.
How many neurons compose the sensory pathways following sympathetic pathways?
A single neuron with a long axon from the sensory receptor to the CNS.
How do pain axons from organs return to spinal nerves?
They travel back through splanchnic and sympathetic nerves without synapsing.
Where do pain pathways from viscera mix once in the CNS?
With somatic pain pathways in the spinal cord.
What causes referred pain from internal organs?
Visceral pain pathways mix with somatic pain pathways.
Where are the cell bodies for minor GVA axons located?
In DRG at the T1 to L2 spinal cord/spinal nerve level.
What type of information do GVA axons/neurons carry?
Physiological information from glands and vessels innervated by sympathetic efferent axons.
What is the main role of the Vagus Nerve (CN X) in the parasympathetic pathways?
It primarily innervates internal organs in the thorax and abdomen.
What is the craniosacral division of the ANS?
It refers to the parasympathetic division that originates in the brain and sacral spinal cord.
Which cranial nerves are associated with preganglionic parasympathetic nuclei in the brainstem?
Cranial nerves III, VII, IX, and X.
What do the postganglionic axons of cranial nerves III, VII, and IX do?
They leave the ganglion and follow branches to reach the target organ.
What is the effect of parasympathetics on target glands?
They increase secretion, making the glands more active.
What is a primary target of the parasympathetic pathways in the head?
Specialized glands and smooth muscles of the eye.
Where are the preganglionic parasympathetic neuron cell bodies of CN III located?
In the Edinger-Westphal Nucleus of the midbrain.
What happens when the parasympathetic system affects the smooth muscle in the eye?
It adjusts for near vision.
Cranial nerves III, VII, IX, and X are connected to preganglionic parasympathetic nuclei in the brainstem.
The Vagus Nerve mainly targets internal organs in the thorax and abdomen as part of the parasympathetic pathways.
The parasympathetic ganglia in the head contain postganglionic neurons associated with the parasympathetic pathway.
What is the primary function of the parasympathetic division?
Regulate rest and digest functions
Increase heart rate
Prepare body for fight or flight
Stimulate sweat glands
Where are postganglionic neuron cell bodies located for the pupil constriction?
In the Ciliary Ganglion (just behind the eyeball).
What are the target organs of postganglionic neurons from the Ciliary Ganglion?
Where are preganglionic parasympathetic neuron cell bodies for CN VII located?
In the Superior Salivatory Nucleus of the pons.
What are the target organs of the Pterygopalatine Ganglion?
What are the target organs of the Submandibular Ganglion?
Where are preganglionic parasympathetic neuron cell bodies for CN IX located?
In the Inferior Salivatory Nucleus of the pons.
What is the target organ of postganglionic neurons from the Otic Ganglion?
Parotid salivary gland outside the mouth (below the ear).
Where are preganglionic parasympathetic neurons for thoracic and abdominal organs located?
In the Dorsal Motor Nucleus of the Vagus (DMN of X).
What happens to the preganglionic axons of CN X?
They descend through the skull and neck to the thorax.
Where are preganglionic parasympathetic neurons for distal gut located?
In the sacral spinal cord at levels S2, S3, & S4.
What is the name of the nucleus in the sacral cord?
It is called the sacral parasympathetic nucleus.
How do the preganglionic axons leave the CNS in the sacral region?
They leave in ventral roots and follow spinal nerves.
What happens to the axons after following spinal nerves?
They separate as distinct parasympathetic nerves to target organs.
What is not necessary when tracing sensory (GVA) axons from glands/smooth muscle of the head?
What is located at the base of the skull related to the vagus nerve?
What is the name of the nucleus in the medulla where sensory axons synapse?
What type of information do GSA neurons carry?
Older models include only GVE neurons; modern models include GVA sensory neurons. GVA neurons convey physiological and nociceptive information.
Higher brain regions like the hypothalamus regulate ANS output. Motor output is primarily from brainstem and spinal cord.
Active during stress; increases heart rate and blood flow to muscles.
Active during relaxation; decreases heart rate and increases gut activity.
Preganglionic sympathetic neurons are in T1-L2, projecting to various target organs.
Preganglionic axons either ascend (upper limb) or descend (lower limb) in the sympathetic chain.
Synapse in the Superior Cervical Ganglion (SCG). Targets include smooth muscles and glands.
Preganglionic neurons in T1-T4; postganglionic targets include heart and lungs.
Synapse in preaortic ganglia; targets mainly gut and its glands.
Primarily via the Vagus Nerve (CN X) to thoracic and abdominal organs.
Cranial nerves III, VII, IX, and X carry parasympathetic axons to various glands.
CN X innervates most gut and abdominal organs, with ganglia in organ walls.
GVA sensory axons relay physiological information from organs, often following similar pathways as sympathetic innervation.
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