FINAL: ANS Flashcards
What is the general pathway for the ANS (include the special divison)
- Autonomic sensory neurons (in visceral organs & blood vessels)
- Integrating Centers (in CNS)
- Autonomic Motor Neurons (propagate from CNS to various effector tissues)
- Enteric Divison (specialized network in wall of GI tract)
What are the effectors for the ANS? and how does the ANS affect each one?
involuntary m:
- Smooth m.: contract/relax
- Cardiac m.: inc./dec. force of contraction
- Glands: inc/dec secretions
How is the ANS organized (3 things)
nerves/ganglia/plexuses
- ganglia/plexuses lie outside of s.c.
What are the 2 systems of the ANS and what is their region?
Sympathetic: thoracolumbar (T1-L2)
Parasympathetic: craniosacral (CIII, CVII, CIX, CX, S2-S4)
Efferent/sensory pathway: where are the neurons found in the grey commissure?
lateral horns (some in ant. horn)
Where are autonomic ganglia (bridge btwn preganglionic and postganglionic neurons) found? (3) List whether they are sympathetic or parasympathetic.
- Sympathetic Trunk (chain): sympathetic
- Prevertebral (collateral) Ganglion: sympathetic
- Terminal (Intramural) Ganglion: parasympathetic
Sympathetic trunk: where is it found?
close on each side of vertebral column (parallel to it)
Prevertebral (collateral) Ganglion: where are they found and what are the specific arteries
ant. to large abdominal arteries
- celiac ganglion
- sup. mesenteric ganglion
- inf. mesenteric ganglion
Sympathetic trunk and paravertebral ganglia receive their preganglionic fibers from:
Thoracolumbar sympathetic division (T1-L2)
Terminal (intramural) ganglion: location
very close to or in visceral effectors (smooth/cardiac m., glands)
Terminal ganglia receive preganglionic fibers directly from:
craniosacral parasympathetic division (CIII, CVII, CIX, CX, S2-S4)
Sympathetic division: preganglionic fibers have cell bodies in?
lateral grey horns of s.c.
Describe the path of sympathetic preganglionic fibers that synapse in the sympathetic trunk
- preganglionic fibers have cell bodies in lateral grey horns of s.c. (T1-L2)
- autonomic efferent fibers leave thru ventral root to join spinal n.
- preganglionic fibers enter sympathetic trunk/chain via White Ramus Communicans
- Synapses here in sympathetic trunk ganglion (or goes up/down to another lvl first)
- postganglionic (unmyelinated) fibers exit via Grey Rami Communicans and re-enter spinal n. (thru ventral or dorsal ramus)
- travels to effector
What are splanchnic nerves?
presynaptic nerves below the diaphragm going to prevertebral ganglia from sympathetic trunk
Describe the path of sympathetic preganglionic fibers that DO NOT synapse in the sympathetic trunk
- preganglionic fibers have cell bodies in lateral grey horns of s.c. (T5-L2)
- autonomic efferent fibers leave thru ventral root to get to spinal n.
- go through White Ramus Communicans
- passes through sympathetic trunk
- continues as splanchnic n.
- synapses in prevertebral ganglion (near major artery)
- postganglionic fiber goes to effector
how many postsynaptic neurons can a presynaptic neuron synapse with? What does this mean for the body?
1 can synapse with as many as 20
- sympathetic responses have a widespread, coordinated effect of the body (fight or flight)
What is another name for the celiac plexus?
solar plexus
What is the celiac plexus comprised of? where is it?
- paired celiac ganglia + sup. mesenteric ganglia + other small ganglia
- lies in ant. aorta at origin of celiac a.
Where are the preganglionic cell bodies of the parasympathetic division found?
- in motor nuclei of CN: III, VII, IX, X
- lateral grey horns of S2-S4
Describe the pathway for parasympathetic preganglionic fibers in the cranial region
- start in nuclei of CN III, VII, IX, X
- continue along cranial n.
- synapse in terminal (intramural) ganglia
- postganglionic neuron innervates effector
Describe the pathway for parasympathetic preganglionic fibers in the sacral region
- start in lateral horns of S2-S4
- exit via ventral root to join sacral spinal nerve
- branches into a pelvic splanchnic nerve
- synapse in terminal (intramural) ganglia
- postganglionic neuron innervates effector
All preganglionic fibers (sympathetic/parasympathetic) release which neurotransmitter?
Acetylcholine
What do postganglionic fibers of the sympathetic division release?
- Norepinephrine (inc. activity)
- sweat glands: ACh
- adrenal medulla: no postganglionic fiber; chromaffin cells release epinephrine and NE
What are adrenergic fibers?
neurons that release NE or epinephrine
- sympathetic postganglionic fibers
