The Autonomic Nervous System
What are the 3 possible routes sympathetic nerves can take after entering the sympathetic trunk?
1. Synapse with ganglionic neuron at the same level. 2. Ascend or descend trunk to synapse at a different ganglion level. 3. Pass through trunk without synapsing.
How many cranial nerves emerge from the brain?
12 pair
What is the efferent pathway of the autonomic nervous system?
2 neuron chain connects CNS with effector tissue
How many spinal nerves emerge from the spinal cord?
31 pair
How many parasympathetic fibers exit the brain?
4
What nerves exit above corresponding vertebrae?
C2-C7
T/F All sympathetic axons exit the spinal cord and synapse in the paravertebral trunk.
F
What is a pneumonic for autonomic nervous system reproductive function?
Point and Shoot Parasympathetic then Sympathetic
Where do parasympathetic fibers exit the spinal cord?
S2-S4
T/F All sympathetic axons exit the spinal cord and enter the paravertebral trunk.
T
What levels are the lateral horns found?
T1-L2
What spinal nerves exit below corresponding vertebrae?
T1-L5
What do parasympathetic post-ganglionic neurons release?
acetylcholine
What is released by all pre-ganglionic axons?
acetylcholine
What is released by sympathetic post-ganglionic neurons to sweat glands?
acetylcholine
Where are the splanchnic nerves largely located?
anterior surface of aorta
Where do axons of the white matter go?
ascending to somatosensory cortex descending from motor cortex communication between left and right halves
Where are motor neurons and therefore the ventral horn and ventral roots present?
at all levels
Where are sensory neurons and therefore the dorsal and dorsal root present?
at all levels
Visceral pain afferents travel back to the spinal cord with what?
autonomic motor efferents
What are the 2 divisions of the motor efferent division of the PNS?
autonomic nervous system somatic nervous system
What neurons are unmyelinated?
post-synaptic
Where does C8 exit?
between C7 and T1
Where does C1 exit?
between the occipital bone and atlas
What makes up the central nervous system?
brain and spinal cord
Where are the pre-ganglionic neuron somas of the craniosacral division housed?
brainstem and S2-S4
Special Visceral Efferent Nerve Fibers
branchial motor axons of motor neurons derived from the branchial arches voluntary motor to skeletal muscles for chewing, facial expression, swallowing, speech functionally analogous to general somatic efferent
The effector of the autonomic nervous system is ...
cardiac, smooth muscle, and glands
What is the network of post-ganglionic axons from the superior cervical ganglion called?
carotid plexus
What is in the dorsal root ganglion?
cell bodies of sensory neurons
What is found within the central canal of the spinal ford?
cerebrospinal fluid
What are the 4 parasympathetic ganglia of the head and neck and what do they innervate?
ciliary ganglion: pupil and lens otic ganglion: parotid salivary gland pterygopalatine ganglion: lacrimal and nasal glands submandibular ganglion: submandibular and sublingual salivary gland
What is the function of the peripheral nervous system?
communication lines between CNS and the rest of the body
What is the function of the sensory afferent division of the PNS?
conducts impulses form receptors to the CNS
What is the function of the autonomic nervous system?
conducts impulses from the CNS to cardiac muscles, smooth muscles, and glands
What is the function of the motor efferent division of the PNS?
conducts impulses from the CNS to effectors (muscles and glands)
What is the function of the somatic nervous system?
conducts impulses from the CNS to skeletal muscles
What is the function of the parasympathetic division of the autonomic nervous system?
conserves energy promotes housekeeping functions during rest
What neurons are myelinated?
pre-ganglionic
What makes up the peripheral nervous system?
cranial nerves and spinal nerves
What is another name for the parasympathetic division?
craniosacral division
What are the sections of the gray matter?
dorsal horn ventral horn intermediate zone lateral horns (T1-L2)
Where are the sensory neuron soma?
dorsal root ganglion
Neurotransmitters (acetylcholine, norepinephrine) are stimulatory/inhibitory.
either; depends on synapse
What does the autonomic nervous system work closely with?
endocrine system
What does the adrenal medulla secrete?
epinephrine and norepinephrine into the bloodstream
In what part of the body is there not innervation by both sympathetic and parasympathetic?
extremities and body wall there is only sympathetic innervation
What parasympathetic cranial nerve effects various facial glands?
facial nerve (VII)
What makes up the spinal nerve?
fusion of the dorsal and ventral roots
What nerve fibers are found in both the cranial and spinal nerves?
general somatic efferent general visceral efferent general somatic afferent general visceral afferent
What parasympathetic cranial nerve effects the parotid salivary gland?
glossopharyngeal nerve (IX)
Where are the effects of the parasympathetic division?
head and body cavities
Where is the spinal cord found?
in the canal formed by vertebral foramen and intervertebral disks
Dorsal Primary Ramus
innervate joints of spinal column, muscles of back, skin of back
Ventral Primary Ramus
innervate remaining lateral and ventral structures or trunk and extremities
What is the function of the central nervous system?
integrative and control centers
The lateral horn corresponds to what?
intermediolateral cell column
Where do the spinal nerves exit?
intervertebral foramen
Where are parasympathetic fibers found?
lateral aspect of intermediate zone at levels S2-S4
Where are sympathetic fibers found?
lateral horns at T1-L2
Where do sympathetic fibers exit the spinal cord?
lateral horns form T1-L2
Where are the pre-ganglionic soma of the thoracolumbar division housed?
lateral horns of spinal cord at levels T1-L2
What is the division between the parasympathetic innervation by the cranial division and by the sacral division?
left colic flexure
In the craniosacral division, which axons are long and which ones are short?
long pre-ganglionic axons short post-ganglionic
What is the role of the autonomic nervous system and endocrine system collectively?
maintains homeostasis of cardiovascular, respiratory, digestive, urinary, and reproductive functions
What is the triad of symptoms for Horner's syndrome?
miosis ptosis anhidrosis
What is the function of the sympathetic division of the autonomic nervous system?
mobilizes body systems during activity
What kind of nerves are in the ventral root?
motor
What kind of neurons are in the ventral horn and ventral roots?
motor
What makes up the motor efferent division of the PNS?
motor nerve fibers
What is the efferent pathway of the somatic nervous system?
motor neuron soma in the the CNS and axons extends to the effector muscle (1 axon)
What makes up the white matter of the spinal cord?
myelinated axons
Where are parasympathetic ganglion located?
near target organ
How does the adrenal medulla function?
pre-ganglionic sympathetic fibers innervate secretory cells and stimulate secretion of epinephrine and norepinephrine into the bloodstream
What are the cranial nerves that carry sympathetic fibers?
none
What is released by most sympathetic post-ganglionic neurons?
norepinephrine
How many sympathetic fibers exit the brain?
o
What are the cranial nerves that carry parasympathetic autonomic fibers?
oculomotor (III) facial (VII) glossopharyngeal (IX) vagus (X)
What parasympathetic cranial nerve effects pupillary constriction and lens reshaping?
oculomotor nerve (III)
Where is the sympathetic trunk?
on each side of the spinal cord extending higher and lower than spinal levels that give rise to it
What makes up the nerve plexuses?
only ventral primary rami
What stimulates erection?
parasympathetic (norepinephrine causes vasodilation)
Where do spinal nerves S1-Co1 exit?
pass through the sacral canal and out the sacral foramina and hiatus
What parasympathetic sacral nerve(s) effect the distal colon and urogenital system?
pelvis splanchnic nerves
What is the role of the parasympathetic division of the autonomic nervous system?
performs maintenance activities and conserves body energy resting and digesting decreases heart rate, blood pressure, respiration constricts pupils activates GI and urinary function
What is the only example of sympathetic and parasympathetic divisions working toward a common goal?
reproductive function
What kind of nerves are in the dorsal root?
sensory
What kind of neurons are in the dorsal horn and dorsal roots?
sensory
Which neurons are short and which axons are long in the thoracolumbar division?
short pre-ganglionic long post-ganglionic
The effector of the somatic nervous system is ...
skeletal muscle
The autonomic nervous system include motor neurons that innervate what?
smooth muscle cardiac muscle glands
Describe the third possible route of sympathetic axons.
soma in lateral horn or spinal cord gray matter axons exit ventral root and enter spinal nerve pass through white communicating ramus to sympathetic trunk pre-ganglionic axon does NOT synapse in trunk exits trunk with one of the splanchnic nerves synapse with ganglionic neuron in one of the other sympathetic ganglia post-ganglionic axon travels to effector tissue
Describe the second possible route of sympathetic axons.
soma in lateral horn or spinal cord gray matter axons exit ventral root and enter spinal nerve pass through white communicating ramus to sympathetic trunk pre-ganglionic axon travels up or down sympathetic trunk to a different level synapse with ganglionic neuron post-ganglionic axon re-enters spinal nerve via gray communicating ramus travels with peripheral nerve to effector tissue
Describe the first possible route of sympathetic axons.
soma in lateral horn or spinal cord gray matter axons exit ventral root and enter spinal nerve pass through white communicating ramus to sympathetic trunk synapse with ganglionic neuron post-ganglionic axon re-enters spinal nerve via gray communicating ramus travels with peripheral nerve to effector tissue
What is makes up the sensory afferent division of the PNS?
somatic and visceral sensory nerve fibers
General Somatic Efferent Nerve Fibers
somatic motor axons of motor neurons for voluntary motor control of skeletal muscle
What makes the somatic nervous system?
somatic motor voluntary nerves
General Somatic Afferent Nerve Fibers
somatic sensory convey touch, pain, temp, pressure, vibration, proprioception of head
Visceral pain afferents are capable of exciting what?
somatic sensory neurons at the same spinal level
Stellate ganglion
sometimes the inferior cervical ganglion and T1 ganglion fuse
Special Sensory Afferent Nerve Fibers
special sensory convey sensory input of vision, hearing, balance, taste, and smell
What nerves fibers are found only in some cranial nerves?
special visceral efferent special sensory afferent
What connects the paravertebral trunk with other sympathetic ganglia?
splanchnic nerves
What is the role of the sympathetic division of the autonomic nervous system?
stimulates effectors during times of activity fight of flight increases heart rate, blood pressure, respiration dilates pupils slows GI and urinary function
The autonomic nervous system operates at what level?
subconscious
What is responsible for all sympathetic innervation to the head and neck?
superior cervical ganglion
What stimulates orgasm?
sympathetic
What are the 2 divisions of the autonomic nervous system?
sympathetic parasympathetic
Cardiopulmonary splanchnic nerve
sympathetic innervation of trunk synapse in trunk
Abdominopelvic splanchnich nerve
sympathetic innervation of visceral organs do not synapse in trunk
The adrenal medulla is functionally part of the ...
sympathetic nervous system.
What is the name of the 2 columns of sympathetic ganglia that flank the spine?
sympathetic paravertebral trunk
What nerve carries information to the thorax and abdomen and where does it originate?
the Vagus nerve originates in the brain
What is the periarterial plexus?
the carotid plexus running along the carotid arteries
Post-ganglionic axons from the superior cervical ganglionic piggyback what?
the common internal carotid arteries
In the autonomic nervous system, what is unmyelinated?
the post-ganglionic axon
In the autonomic nervous system, what is myelinated?
the pre-ganglionic axon
The adrenal medulla works with what?
the sympathetic division in stimulate effector organs
Where does the superior cervical ganglion receive communication from?
the upper thoracic levels of the spinal cord
What is another name for the sympathetic division?
thoracolumbar division
What causes Horner's syndrome?
unilateral damage to the cervical sympathetic trunk causes a loss of sympathetic input to some head functions
What parasympathetic cranial nerve is the major nerve for the thorax and abdomen viscera?
vagus nerve (X)
How do sympathetic pre-ganglionic axons exit the spinal cord?
via ventral roots
How do sympathetic pre-ganglionic axons enter the sympathetic trunk?
via white rami communicantes
What does the autonomic nervous system control?
visceral body functions
What kind of neurons are in the lateral horn?
visceral motor
General Visceral Efferent Nerve Fibers
visceral motor axons of preganglionic parasympathetic neurons for smooth muscle and glands
What makes up the autonomic nervous system?
visceral motor involuntary nerves
What are 2 other names for the autonomic nervous system?
visceral nervous system involuntary nervous system
What does referred visceral pain mean?
visceral pain afferents excite somatic neurons at the same spinal level and so can give the impression that the pain is originating from the associated dermatome
General Visceral Afferent Nerve Fibers
visceral sensory convey sensory input from viscera (pain, blood pressure, etc)
