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53 Cards in this Set

  • Front
  • Back
Somatic efferent
Produces voluntary skeletal muscle contractions
Autonomic (visceral efferent)
System consists of:
gen. visceral sensory (afferent)neurons
gen. visceral motor (efferent) neurons
visual effectors
involuntarily regulates visceral activities
Sympathetic nervous system
Parasympathetic nervous system
efferent fibers: preganglionic and postganglionic
many visceral organs have dual innervation - not all
Visceral effectors
smooth and cardiac muscle
Autonomic nervous system
Sympathetic nervous system
Parasympathetic nervous system
Sympathetic nervous system
prepares the body for stress
Parasympathetic nervous system
producing a "rest relaxation" response
Visceral efferent fibers
Preganglionic fibers
Postganglionic fibers
Preganglionic fibers
Run from the c.n.s. to autonomic ganglia
Postganglionic fibers
Run from autonomic ganglia to visceral effectors
"autonomic ganglia"
A ganglion occurs btwn. preganglionic and postganglionic fibers
Sympathetic nervous system
Preganglionic neurons (thoracolumbar outflow)
Autonomic ganglia
Sympathetic trunk ganglia
Prevertebral ganglia
Autonomic plexuses
Postganglionic neurons
White rami communicants
Gray rami communicants
Why is the sympathetic response (stress reaction) so widespread in the body?
"1" preganglionic fiber can stimulate up to "20" plus postganglionic neurons that supply different organs - thus stress reaction widespread
neurotransmitters get into blood and remain a while before being broken down.
Visceral efferent pathways
consists of two neurons:
Preganglionic neurons
Postganglionic neurons
Preganglionic neurons
run from C.N.S. to ganglion
Most are myelinated (white) fibers
Postganglionic neurons
run from ganglion to visceral effectors
Are unmyelinated (gray) fibers
Preganglionic neurons
thoracolumbar division
Cell bodies originate in lateral gray horns of T1 - T2
Axons terminate in autonomic ganglia of the s.n.s.
Prevertebral ganglia (collateral)
Sup. mesenteric ganglion
Inf. mesenteric ganglion
Splanchnic nerves
Are preganglionic neurons
belong to s.n.s.
bypass or pass through sympathetic trunk and terminate in collateral ganglia
Autonomic plexuses
In thorax
abdomen and pelvic region of body
are network of axons of both sympathetic and parasympathetic neurons
Preganglionic neurons (craniosacral outflow)
Cell bodies of parasympathetic in nuclei of cranial nerves III, VII, IX, and X and lateral gray horns of S2 - S4 (sacral parasympathetic outflow)
Axons terminate in autonomic ganglia of the P.N.S.
Postganglionic neurons
Cell bodies from autonomic ganglia (sym. trunk and collateral ganglia - terminate in visceral effectors)
White rami communicants
Branches - connect ventral root of sp. nerve with sympathetic trunk
are myelinated preganglionic fibers
Gray rami communicants
Run from ganglia back to ventral ramus of sp. nerve
are gray postganglionic neurons
Autonomic ganglia of P.N.S.
Terminal ganglia (intramural)
May be divided into 3 gen. groups
sympathetic division
parasympathetic division
Terminal (intramural) ganglia
Preganglionic axons of the parasympathetic division synapse with postganglionic neurons
located close to or actually within the wall of a visceral organ.
longer the most axons of sympathetic preganglionic EXAMPLES
Postganglionic neurons
The 2nd autonomic neuron in an autonomic pathway having its cell body an dendrites located in an autonomic ganglion and it's a myelinated axon ending at cardiac muscle, smooth muscle, or a gland.
Ap. 50 + known
one neuron may contain several types
Released at:
Neuroeffector junction
Cholinergic fibers
Adrenergic fibers
space btwn. axonal ending and dendrite or effector
Neuroeffector junctions
Specifically btwn. postganglionic axonal ending and effector
Cholinergic fibers
release acetylcholine (Ach)
is released at:
Sympathetic and parasympathetic preganglionic axons
All parasympathetic postganglionic axons
Few sympathetic postganglionic axons
Ach inactivated by acetycholinesterase (AchE)
esp. excites - as in the contraction of skeletal muscle - but - it can also inhibit cardiac muscle - thus receptors determine effect of neurotransmitters
Adrenergic fibers
released norepinephrine
released at most sympathetic postganglionic axons
inactivated slowly by:
Catechol-o-methyltransferase (COMT)
Monoamine oxidase (MAO)
may enter the bloodstream
secreted from adrenal medulla
Sympathetic reaction
prepares body for stress - "fight or flight" response
Parasympathetic reaction
restores and/or conserves energy - "rest and repair" response
Sweat glands
(visceral effector)
s.n.s stimulation: secretion gen. up
p.n.s stimulation: no known innervation
Gastric secretion
(visceral effector)
s.n.s stimulation: secretion inhibited
p.n.s stimulation: increased secretion
Muscles of bronchi
(visceral effector)
s.n.s stimulation: relation leads airway dialation
p.n.s stimulation: contraction leads to airway contriction
Heart rate
Force of contraction
(visceral effector)
s.n.s stimulation: Increased heart rate and force of atrial and ventrile contractions
p.n.s stimulation: Decrease heart rate and Decreased force of atrial contraction
Blood vessels to:
Skin (periphery)
Skeletal muscles
(visceral effector)
s.n.s stimulation: Contraction leads to vasocontriction; relaxation leads to vasodialation
p.n.s stimulation: Vasodialation, which may not be physilogically significant
S.M. No known effect
(visceral effector)
s.n.s stimulation: decreases
motility and tone; contraction of sphincters
p.n.s stimulation: Increased motility and tone; relaxation of sphincters
Visceral autonomic reflexes
Consists of:
Afferent(sensory) neuron
Association neuron
Visceral efferent preganglionic neuron
Visceral efferent postganglionic neuron
Visceral effector
Visceral autonomic reflexes
responses that occur when nerve impulses pass over an autonomic reflex arc
regulating controlled condition of body - blood pressure - digestion
distal end of sensory neuron
responds to a stimulus and produces a change that will ultimately trigger nerve impulses.
Sensory (afferent) neurons
Conducts nerve impulses from receptors to the CNS.
Association neuron
A nerve cell found entirely within the central nervous system that acts as a link between sensory neurons and motor neurons.
Visceral efferent
smooth muscle
cardiac muscle
receives input from or is linked to:
Higher brain centers
Visceral functions
appears to be controlled by post. and lat. portions of the hypothalamus.
appears to be controlled by ant. and med. portions of the hypothalamus.
mind and body
trance like state
clearing your mind for relaxation
A technique in which an individual is provided w/ info regarding an autonomic response such as heart rate, blood pressure, or skin temp. using electronic devices
Progressive relaxation
tense and relax different parts of body and then learning how to relax those muscles.