Autonomic Nervous System
7. Sympatheic Postganglionic axons travel to target organs
-cell body located in autonomic ganglia -travel to and innervate target organs
postganglionic neuron
-cell body located in autonomic ganglion -axon terminates on end of organ
Preganglionic neuron
-cell body located in brain or spinal cord -axon will synapse (exchange nerve impulse) is autonomic ganglion with postganglionic neuron -all are myleniated
4. Gray Rami
-contains sympathetic postganglionic axons -from sympathetic trunk to spinal nerve -"exit ramp" found on all spinal nerves -unmelyinated -take out info to all nerves
Parasympathetic Nervous System (Carniosacral System)
-cranial axons are part of CN III (oculomotor), VII (Facial), IX (Glossopharyngeal), and X (Vagus) -sacral axons originate in S2-S4 segments of spinal cord -maintains homeostatic environments -resting and digesting -innervates head, neck, trunk only NO PARASYMPATHETIC INNERVATION TO LIMBS -activity usually discrete and localized
Spinal Nerve Pathway
-innervates blood vessels, glands in skin -preganglionic axon snapses in sympathetic trunk in ganglion -postganglionic axon leaves sympathetic trunk in gray ramus, travels in spinal nerve to skin
Postganglionic Sympathetic Nerve Pathway
-innervating internal thoracic organs -preganglinoic axon synapses in sympathetic trunk ganglion -postganglionic axon does NOT leave the trunk via gray ramus -instead postganglionic axon extends anteriorly form the trunk and goes to the thoracic organ
Referred Visceral Pain
-is felt not in the visceria itself, but int eh area (dermatome) supplied by the same segments of the spinal cord -cause is unknown-could be sensory nerve fibers form the viscera and the dermatome in question terminate on the same neurons in the spinal cord, and that the brain has trouble distinguishing between the 2 sites
3. Sympathetic Trunks (Sympathetic Trunk (paravetebral) ganglia
-long chains of axons, on eitehr side of vertebral column from cervical portion of cord to sacral portion-contains sympathetic trunk ganglia -some preganglionic axons synapse here -sympathetic highway -where lots of pre/postganglionic meet up
1. intermediolateral cell column (lateral horn) of spinal cord (part of gray matter)
-present in T1-L2 segements of spinal cord only -cell bodies of preganglionic sympathetic nerves located here -preganglionic axons exit via anterior root, spinal nerve, go into white ramus
Afferent Component of ANS
-relay sensory into about viscern (BP, smooth muscle tone) -most of time not consciously aware of this info -sensory neurons travel form organ, through sympathetic trunk to cell body of sensory neuron located in posterior root ganglion
2. White Rami
-runs from anterior ramus of spinal nerve to sympathetic trunk -is more lateral of the two connections to sympathetic trunk -found ONLY on spinal nerves T1-L2 -"entrance ramp" to sympathetic trunk -myleniated
6. Prevertebral (Collateral ) Ganglia
-splanchnic nerves synapse here -located in front of vertebral column and anterior to abdominal aorta -some have special names
5. Splanchnic Nerves
-they are preganglinic axons that do not synapse in paravertebral ganglia -splanchnic nerves come off anterior part of trunk and travel to prevertebral ganglia
Pathways for preganglionic sympathetic axons all start with the same 5 steps
1. axons from pregnglionic neurons leave the lateral horn 2. travel through anterior root 3. go to spinal nerve 4. enter sympathetic trunk via white ramus 5. Preganglionic axons may travel up or down sympathetic trunk
Pathway of Parasympathetic NS
1. axons of preganglionic neurons leave brainstem via (cranial nerves, spinal cord, pelvic splanchic nerves) 2. preganglionic axons synapse in named cranial grnglion or in terminal ganglion located close to organ 3. Post ganglionic axon travels to effector organ
4 f's of autonomic nervous system
1. feeding 2. fleeing 3. fighting 4. ... sexual behavior
Components of Sympathetic NS
1. intermediolateral cell column (lateral horn) of spinal cord (part of gray matter) 2. White Rami 3. Sympathetic Trunks (Sympathetic Trunk (paravetebral) ganglia 4. Gray Rami 5. Splanchnic Nerves-they are preganglinic axons that do not synapse in paravertebral ganglia 6. Prevertebral (Collateral ) Ganglia 7. Sympatheic Postganglionic axons travel to target organs
Components of ParaNS
1. preganglionic motor neurons 2. preganglionic parasympathetic nerves offf the S2-S4 called pelvic splanchnic nerves 3. terminal ganglia
Somatic Nervous System
Innervates skeletal muscles and receives sensory info from senses Voluntary Nervous System
Parasympathetic Nerves
LONG preganglioinic axons, short postganglionic axons -nerves that come off spinal cord off the S2-S4 are called pelvic splanchnic nerves-helps faciliate mass action effect
Sympathetic Motor Nerves
Tends to have short preganglionic axons, and long postganglionic axons -Originate in T1-L2 segments of spinal cord
Sympathetic Nervous System (Thoracolumbar System)
all ganglion occured in thoraic/lumbar region axons originate in T1-L2 segments of spinal cord emergency situations (fight or flight) "mass action" effect-in general everything gets turned on when sympathetic NS turns on
Reasons why autonomic motor component uses 2 neurons
having 2 neuron chain can create a lot of neurons firing -have preganglionic neuron send info to ganglion-then have ganglion send out tons of neural info -converge info at ganglion (hub) then diverge out info
Splanchnic Nerve Pathway
innerates abdominal and pelvic organs -preganglionic axon does NOT synapse in sympathetic trunk ganglion, but leaves sympathetic trunk as a splanchnic nerve -splanchnic nerve travels to prevertebral ganglion, synapses with postganglionic neuron -postganglionic axon goes to abdominal/pelvic organ
Autonomic Nervous System
part of nervous system concerned with Involuntary activity and internal environment Innervates smooth/cardiac muscle and glands Involuntary nervous system Concerned with internal environment
Autonomic Motor
uses 2 neurons to go from spinal cord to the target tissue
Somatic Motor
uses a singe neuron to go form spinal cord to skeletal muscle
