NURS 163 Chapter Notes - Chapter 11: Nicotinic Acetylcholine Receptor, Reticular Formation, Cholinergic
Study guide 11: ANS answers
1. Sensory arm of ANS: (visceral reflex arcs)
1) Receptors:
a. Interceptors: visceral organs
b. Chemoreceptors: monitor blood chemical levels
c. Mechanoreceptors: monitor organ stretch
2) Sensory neuron
3) Integration center: visceral reflexes ALWAYS polysynaptic
4) Motor output: conducted via autonomic pathway
a. Efferent pathway: 2 neurons
i. Preganglionic: input → outside CNS ganglia
ii. Postganglionic: receives preganglionic input, signal → effector
5) Effector: smooth/cardiac muscle/glands
2. Motor pathways of somatic nervous system (SNS) vs. ANS
1) Both: output begins in CNS
2) ANS: two motor neuron in series
a. First neuron: preganglionic neuron
i. Preganglionic: lightly myelinated
b. Synapses with postganglionic neuron (2nd neuron)
i. Postganglionic: nonmyelinated
c. Postganglionic axons (para/symp) extend to effectors
d. Sympathetic fibers: synapse close to CNS (short preganglionic)
e. Parasympathetic fibers: synapse far from CNS (long preganglionic)
3) SNS: single lower motor neuron
a. Myelinated fibers
b. Effectors: skeletal muscles
c. NT @ neuroeffector jxn: ACh (stimulatory)
3-5. Preganglionic vs. postganglionic neuron:
1) Preganglionic: 1st neuron in sensory ANS pathway
a. Sympathetic: shorter
b. Parasympathetic: longer
c. Origin: CNS
d. Ganglia location: synapses w/ 2nd order neuron
e. NT: ACh @ synapse w/ ganglion
2) Postganglionic: 2nd neuron
a. Sympathetic: longer
b. Parasympathetic: shorter
c. Origin: outside CNS
d. Ganglia location: extends to effector
e. NT: ACh & NE @neuroeffector synapse
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6. CNS origins of parasympathetic ANS fibers:
A. Brain stem nuclei: CN III, VII, IX, X
a. Leave brainstem w/ SNS motor neurons
B. Sacral nuclei: leave CNS via ventral roots
7. Where is the parasympathetic preganglionic/postganglionic synapse?
A. Long preganglioni synapse /…
a. Intramural ganglia: in wall of effector
b. Terminal ganglia: close to effector
8-9. Body regions/organs served by parasympathetic preganglionic fibers of…
CN: III, VII, IX, X?
A. CN III: smooth muscles of eye (accommodation of lens)
B. CN VII: secretory activity of nasal, lacrimal, salivary glands
C. CN IX: secretory activity of salivary glands (parotid)
D. CN X: innervates heart, lungs, esophagus, abdominal viscera
10-11. Nerves carrying parasympathetic preganglionic fibers of S2-S4:
A. Sacral outflow: neurons of lateral horns form pelvic nerves
B. Innervate: colon, bladder, reproductive organs
12. Where does the sympathetic (thoracolumbar) division arise?
A. Arise from ventral roots of T1-L2
B. (Cell bodies in lateral horns)
13. Pathway of sympathetic preganglionic fibers from spinal cord → paravertebral
ganglion:
1) Leave cord via ventral roots
2) → White ramus communicans
3) → Paravertebral ganglion (sympathetic chain ganglion) @same level of cord
14. Three things that can happen to preganglionic fiber in paravertebral ganglion:
1) Synapse w/ postganglionic neuron in paravertebral ganglion @ same level
2) Ascend/descend chain, synapse w/ postganglionic @higher/lower level
3) Pass through sympathetic chain w/o synapsing (synapses farther away)
15. Are white rami communicantes OR gray rami communicantes more numerous?
A. Gray rami communicantes: exist @ all levels of the spinal cord
a. Carry postganglionic fibers to destination
b. Carry preganglioni fiers that didn’t synapse in paraerteral ganglia
B. White rami communicantes: exist only @T1-L2 levels
a. Carry preganglionic nerve fibers → paravertebral ganglia
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Document Summary
Where is the parasympathetic preganglionic/postganglionic synapse: long preganglioni(cid:272) synapse (cid:449)/ , intramural ganglia: in wall of effector, terminal ganglia: close to effector. Body regions/organs served by parasympathetic preganglionic fibers of . Autonomic (visceral) reflex arc: reflexes activate smooth/cardiac muscles/glands. White ramus communicans: myelinated structure preganglionic sympathetic fibers pass through when leaving spinal cord via ventral root. Gray ramus communicans: non-myelinated structure postganglionic sympathetic fibers pass through to reach effector organs. Sympathetic chain ganglion (paravertebral ganglion): neuron cell bodies that lie in a vertical row on each side of vertebral column to form sympathetic trunk. Prevertebral ganglion (collateral ganglion): ganglia located anterior to vertebral column only occurring in the abdomen & pelvis. Abdominal aortic plexus: autonomic plexus surrounding abdominal aorta. Terminal ganglion (intramural ganglion): parasympathetic postganglionic in/near effector organ. Cholinergic fiber: fiber that releases ach as nt; all preganglionic fibers & parasympathetic postganglionic fibers. Cholinergic receptor: receptor that binds to ach (nicotinic or muscarinic)
