NURS 301 Lecture Notes - Lecture 5: Autonomic Nervous System, Postganglionic Nerve Fibers, Sympathetic Ganglion
Parasympathetic vs. Sympathetic
Sympathetic
Fight or flight responses for increased physical activity
○
Increases heart rate and blood glucose
○
Reduces blood flow to skin and GI tract
○
-
Parasympathetic division
Rest and digest responses with calming effects
○
Decreases heart rate
○
Stimulates digestion and waste elimination
○
-
Autonomic tone: balance between activity of sympathetic and
parasympathetic tone
-
Comparison of Neural Pathways of Somatic and Autonomic
Divisions
Somatic efferent innervation
1 motor neuron to skeletal muscle
○
ACh
○
-
Autonomic efferent innervation
Preganglionic neuron and synapses in ganglion with post
ganglionic fiber
Unmyelinated postganglionic fiber (axon)
§
○
Ach or NE
○
-
Comparison of the Somatic and Autonomic Nervous Systems
Feature
Somatic
Autonomic
Effectors
Skeletal muscles
Glands, smooth
muscle, cardiac
muscles
Control Usually voluntary Usually involuntary
Efferent pathways One nerve fiber from
CNS to effector; no
ganglia
Two nerve fibers
from CNS to
effector; synapse at
ganglion
Distal nerve
endings
Neuromuscular
junctions
Varicosities
Releases
neurotransmitte
r, releases to
numerous cells
-
Neurotransmitters ACh ACh and
norepinephrine
(NE)
Effect on target cell Always excitatory Excitatory or
inhibitory
Effect of
denervation
Flaccid paralysis Denervation
hypersensitivity, put
in more receptors to
neurotransmitter,
more sensitive to
them
General Actions of the ANS
Involuntary control of glands, cardiac muscle, and smooth
muscle
Visceral reflexes
○
Unconscious, automatic, responses of visceral effectors to
stimuli
○
Example: a rise in blood pressure triggers a reflexive
decrease in heart rate
○
-
ANS not required for effector activity, but ANS modulates the
activity
Example: heart cells still beat without ANS, innate beating
rate of ~100BPM (intrinsic rate)
○
-
Comparison of sympathetic and parasympathetic division
Sympathetic Division
Thoracolumbar division
Preganglionic somas are in lateral horns of spinal
cord
§
○
Short preganglionic fibers, long postganglionic fibers out
to the target tissues
○
Sympathetic chain ganglia (paravertebral ganglia) from
cervical to coccygeal levels
Chains go all the way to coccyx region
§
○
Sympathetic Pathways (right) compared to somatic
efferent pathways (left)
Both on each side
§
Sympathetic
3 BRANCHES
□
§
Spinal nerve route
Preganglionic neuron going out through spinal
nerve
□
§
Sympathetic nerve route
Synapsing in ganglia
□
Take impulses out to head and thoracic regions
□
§
Splanchnic nerve route
Don't synapse with this one, go all the way
through the ganglia and reach a collateral ganglia
towards the front of the spinal cord
□
§
○
-
Adrenal Glands
Located atop kidneys
-
Adrenal cortex
Outer part
○
Secretes hormones
○
-
Adrenal medulla
Inner part
○
Secretes epinephrine, norepinephrine
○
Resembles a sympathetic ganglion
○
-
The Parasympathetic Division
Craniosacral division
-
Long preganglionic fibers synapses with short postganglionic
fibers
-
Terminal ganglia are in or near target organ
-
Selective in its stimulation of target organs
-
Fibers found within four cranial nerves
CN III Oculomotor nerve controls lens and pupils
○
CN VII Facial nerve controls tear, salivary, nasal glands
○
CN IX Glossopharyngeal nerve controls salivary glands
○
CN X Vagus nerves provides branches for heart, lungs,
esophagus and other organs
Contains about 90% of parasympathetic
preganglionic fibers
§
○
-
Sacral parasympathetic fibers form pelvic splanchnic nerves
-
Comparison of Sympathetic and Parasympathetic division
Feature Sympathetic Parasympathetic
Origin in
CNS
Thoracolumbar Craniosacral
Location
of ganglia
Paravertebral ganglia adjacent to
spinal column and prevertebral
ganglia anterior to it
Terminal ganglia
near or within
target organs
Fiber
lengths
Short preganglionic, long
postganglionic
Long
preganglionic,
short
postganglionic
Neuronal
divergence
Extensive Minimal
Effects of
system
Often widespread and general More local and
specific
Sympathetic and Parasympathetic Branches can be transmitters
by their neurotransmitters and receptors
Both sympathetic and parasympathetic preganglionic neurons
acetylcholine onto cholinergic receptors on postganglionic
neurons
-
Most postganglionic sympathetic neurons secrete
norepinephrine onto adrenergic receptors on the target cells
-
Most postganglionic parasympathetic neurons secrete
acetylcholine onto cholinergic receptors on the target cells
-
Acetylcholine (neurotransmitter)
Acetylcholine secreting cells called "cholinergic" fibers
-
Cells influences by ACh have cholinergic receptors
-
Muscarinic receptors are on involuntary effectors
Mushroom toxin
○
Depending on which type, can be excitatory or inhibitory
○
-
Nicotinic receptors are on postganglionic neurons
Tobacco plant toxins, excitatory on target cells
○
-
Norepinephrine (NE) (neurotransmitter)
Secreting cells called "adrenergic" fibers
-
Secreted by sympathetic postganglionic neurons
-
Cells influenced by NE have adrenergic receptors
Alpha-adrenergic receptors on some effector target cells
Excitatory effect on target cells
§
○
Beta-adrenergic receptors on some effector target cells
Inhibitory effect on target cells
§
○
-
How does it work?
The two divisions can affect body organs different because
their postganglionic neurons release different
neurotransmitters and the effectors possess different
adrenergic (e.g. alpha, beta, with sub types) and
cholinergic (e.g. muscarinic, nicotinic) receptors
○
Different receptors can respond to the same
neurotransmitter with varying affinities
○
There can also be differences in target cell receptor signal
messenger mechanisms
○
Most body organs are innervated by both divisions which
typically work in opposition to each other
Most normal activities
Heart rate
□
Blood flow through tissues
□
Blood pressure
□
Temperature
□
Regulation
□
Water balance
□
§
Duel innervation of the Iris
Most viscera contain fibers from both autonomic
divisions
□
Divisions may have antagonistic or cooperative
effects
□
Antagonistic effect on same cells
□
Cooperative effect on different cells for unified
results
□
Sympathetic allows more light to come in the
eye
□
Parasympathetic restrict the pupil and prevent
light from coming in
□
§
Control without dual innervation
Vasomotor control (blood flow) with more or
less sympathetic nerve impulse
No parasympathetic involvement
®
□
More sympathetic impulses ---> causes
constriction and vasoconstrictor, blood vessel
gets smaller
□
Less impulses ---> blood vessels dilate, relax, get
larger
□
§
○
-
Effects of the Sympathetic and Parasympathetic Nervous
System
Target Effect of
Sympathetic
Division
Effect of
Parasympatheti
c Division
Bronchioles Bronchodilatio
n
Bronchoconstrict
ion
Kidneys Reduced urine
output
No effect
Muscle of bladder wall No effect Contraction,
emptying
bladder
Salivary glands Thick mucous
secretion
Thin serious
secretion
Gastrointestinal motility Decreased Increased
Gastrointestinal secretion Decreased Increased
Liver Glycogen
breakdown
Glycogen
synthesis
Pancreatic enzyme secretion Decreased Increased
Penis and clitoris Loss of
erection
Erection
Ejaculation (smooth muscle
roles-sperm propulsion and
glandular secretion)
Stimulation No effect
Central Controls
Autonomic output originates in CNS
-
The efferent neurons of the autonomic division are closely
linked to homeostatic control centers in the hypothalamus,
pons, and medulla
-
What happens when you swerve to miss hitting a bicyclist?
Increased heart rate and respiratory rate as a result of a
situation you are aware of
○
-
The Enteric (Digestive) Nervous System
Digestive tract has its own nervous system
-
Innervates smooth muscle of gastrointestinal tract and glands
-
Regulates
Motility of the esophagus, stomach, and intestines
○
Secretion of digestive enzymes and acid
○
-
Also controlled by the parasympathetic and sympathetic
division of ANS
-
More activity when you eat something
-
Less activity when you haven't ate anything
-
Chagus Disease
Trpanosoma cruzi destroys autonomic ganglia
-
Bites you, regurgitates into your blood
-
Ganglia are infected, fibers are abnormal
-
Online Lecture - Week 5 (Autonomic Nervous
System)
Friday, April 27, 2018
2:00 PM
Parasympathetic vs. Sympathetic
Sympathetic
Fight or flight responses for increased physical activity
○
Increases heart rate and blood glucose
○
Reduces blood flow to skin and GI tract
○
-
Parasympathetic division
Rest and digest responses with calming effects
○
Decreases heart rate
○
Stimulates digestion and waste elimination
○
-
Autonomic tone: balance between activity of sympathetic and
parasympathetic tone
-
Comparison of Neural Pathways of Somatic and Autonomic
Divisions
Somatic efferent innervation
1 motor neuron to skeletal muscle
○
ACh
○
-
Autonomic efferent innervation
Preganglionic neuron and synapses in ganglion with post
ganglionic fiber
Unmyelinated postganglionic fiber (axon)
§
○
Ach or NE
○
-
Comparison of the Somatic and Autonomic Nervous Systems
Feature Somatic Autonomic
Effectors Skeletal muscles Glands, smooth
muscle, cardiac
muscles
Control Usually voluntary Usually involuntary
Efferent pathways One nerve fiber from
CNS to effector; no
ganglia
Two nerve fibers
from CNS to
effector; synapse at
ganglion
Distal nerve
endings
Neuromuscular
junctions
Varicosities
Releases
neurotransmitte
r, releases to
numerous cells
-
Neurotransmitters ACh ACh and
norepinephrine
(NE)
Effect on target cell Always excitatory Excitatory or
inhibitory
Effect of
denervation
Flaccid paralysis Denervation
hypersensitivity, put
in more receptors to
neurotransmitter,
more sensitive to
them
General Actions of the ANS
Involuntary control of glands, cardiac muscle, and smooth
muscle
Visceral reflexes
○
Unconscious, automatic, responses of visceral effectors to
stimuli
○
Example: a rise in blood pressure triggers a reflexive
decrease in heart rate
○
-
ANS not required for effector activity, but ANS modulates the
activity
Example: heart cells still beat without ANS, innate beating
rate of ~100BPM (intrinsic rate)
○
-
Comparison of sympathetic and parasympathetic division
Sympathetic Division
Thoracolumbar division
Preganglionic somas are in lateral horns of spinal
cord
§
○
Short preganglionic fibers, long postganglionic fibers out
to the target tissues
○
Sympathetic chain ganglia (paravertebral ganglia) from
cervical to coccygeal levels
Chains go all the way to coccyx region
§
○
Sympathetic Pathways (right) compared to somatic
efferent pathways (left)
Both on each side
§
Sympathetic
3 BRANCHES
□
§
Spinal nerve route
Preganglionic neuron going out through spinal
nerve
□
§
Sympathetic nerve route
Synapsing in ganglia
□
Take impulses out to head and thoracic regions
□
§
Splanchnic nerve route
Don't synapse with this one, go all the way
through the ganglia and reach a collateral ganglia
towards the front of the spinal cord
□
§
○
-
Adrenal Glands
Located atop kidneys
-
Adrenal cortex
Outer part
○
Secretes hormones
○
-
Adrenal medulla
Inner part
○
Secretes epinephrine, norepinephrine
○
Resembles a sympathetic ganglion
○
-
The Parasympathetic Division
Craniosacral division
-
Long preganglionic fibers synapses with short postganglionic
fibers
-
Terminal ganglia are in or near target organ
-
Selective in its stimulation of target organs
-
Fibers found within four cranial nerves
CN III Oculomotor nerve controls lens and pupils
○
CN VII Facial nerve controls tear, salivary, nasal glands
○
CN IX Glossopharyngeal nerve controls salivary glands
○
CN X Vagus nerves provides branches for heart, lungs,
esophagus and other organs
Contains about 90% of parasympathetic
preganglionic fibers
§
○
-
Sacral parasympathetic fibers form pelvic splanchnic nerves
-
Comparison of Sympathetic and Parasympathetic division
Feature Sympathetic Parasympathetic
Origin in
CNS
Thoracolumbar Craniosacral
Location
of ganglia
Paravertebral ganglia adjacent to
spinal column and prevertebral
ganglia anterior to it
Terminal ganglia
near or within
target organs
Fiber
lengths
Short preganglionic, long
postganglionic
Long
preganglionic,
short
postganglionic
Neuronal
divergence
Extensive Minimal
Effects of
system
Often widespread and general More local and
specific
Sympathetic and Parasympathetic Branches can be transmitters
by their neurotransmitters and receptors
Both sympathetic and parasympathetic preganglionic neurons
acetylcholine onto cholinergic receptors on postganglionic
neurons
-
Most postganglionic sympathetic neurons secrete
norepinephrine onto adrenergic receptors on the target cells
-
Most postganglionic parasympathetic neurons secrete
acetylcholine onto cholinergic receptors on the target cells
-
Acetylcholine (neurotransmitter)
Acetylcholine secreting cells called "cholinergic" fibers
-
Cells influences by ACh have cholinergic receptors
-
Muscarinic receptors are on involuntary effectors
Mushroom toxin
○
Depending on which type, can be excitatory or inhibitory
○
-
Nicotinic receptors are on postganglionic neurons
Tobacco plant toxins, excitatory on target cells
○
-
Norepinephrine (NE) (neurotransmitter)
Secreting cells called "adrenergic" fibers
-
Secreted by sympathetic postganglionic neurons
-
Cells influenced by NE have adrenergic receptors
Alpha-adrenergic receptors on some effector target cells
Excitatory effect on target cells
§
○
Beta-adrenergic receptors on some effector target cells
Inhibitory effect on target cells
§
○
-
How does it work?
The two divisions can affect body organs different because
their postganglionic neurons release different
neurotransmitters and the effectors possess different
adrenergic (e.g. alpha, beta, with sub types) and
cholinergic (e.g. muscarinic, nicotinic) receptors
○
Different receptors can respond to the same
neurotransmitter with varying affinities
○
There can also be differences in target cell receptor signal
messenger mechanisms
○
Most body organs are innervated by both divisions which
typically work in opposition to each other
Most normal activities
Heart rate
□
Blood flow through tissues
□
Blood pressure
□
Temperature
□
Regulation
□
Water balance
□
§
Duel innervation of the Iris
Most viscera contain fibers from both autonomic
divisions
□
Divisions may have antagonistic or cooperative
effects
□
Antagonistic effect on same cells
□
Cooperative effect on different cells for unified
results
□
Sympathetic allows more light to come in the
eye
□
Parasympathetic restrict the pupil and prevent
light from coming in
□
§
Control without dual innervation
Vasomotor control (blood flow) with more or
less sympathetic nerve impulse
No parasympathetic involvement
®
□
More sympathetic impulses ---> causes
constriction and vasoconstrictor, blood vessel
gets smaller
□
Less impulses ---> blood vessels dilate, relax, get
larger
□
§
○
-
Effects of the Sympathetic and Parasympathetic Nervous
System
Target Effect of
Sympathetic
Division
Effect of
Parasympatheti
c Division
Bronchioles Bronchodilatio
n
Bronchoconstrict
ion
Kidneys Reduced urine
output
No effect
Muscle of bladder wall No effect Contraction,
emptying
bladder
Salivary glands Thick mucous
secretion
Thin serious
secretion
Gastrointestinal motility Decreased Increased
Gastrointestinal secretion Decreased Increased
Liver Glycogen
breakdown
Glycogen
synthesis
Pancreatic enzyme secretion Decreased Increased
Penis and clitoris Loss of
erection
Erection
Ejaculation (smooth muscle
roles-sperm propulsion and
glandular secretion)
Stimulation No effect
Central Controls
Autonomic output originates in CNS
-
The efferent neurons of the autonomic division are closely
linked to homeostatic control centers in the hypothalamus,
pons, and medulla
-
What happens when you swerve to miss hitting a bicyclist?
Increased heart rate and respiratory rate as a result of a
situation you are aware of
○
-
The Enteric (Digestive) Nervous System
Digestive tract has its own nervous system
-
Innervates smooth muscle of gastrointestinal tract and glands
-
Regulates
Motility of the esophagus, stomach, and intestines
○
Secretion of digestive enzymes and acid
○
-
Also controlled by the parasympathetic and sympathetic
division of ANS
-
More activity when you eat something
-
Less activity when you haven't ate anything
-
Chagus Disease
Trpanosoma cruzi destroys autonomic ganglia
-
Bites you, regurgitates into your blood
-
Ganglia are infected, fibers are abnormal
-
Online Lecture - Week 5 (Autonomic Nervous
System)
Friday, April 27, 2018
2:00 PM
Parasympathetic vs. Sympathetic
Sympathetic
Fight or flight responses for increased physical activity
○
Increases heart rate and blood glucose
○
Reduces blood flow to skin and GI tract
○
-
Parasympathetic division
Rest and digest responses with calming effects
○
Decreases heart rate
○
Stimulates digestion and waste elimination
○
-
Autonomic tone: balance between activity of sympathetic and
parasympathetic tone
-
Comparison of Neural Pathways of Somatic and Autonomic
Divisions
Somatic efferent innervation
1 motor neuron to skeletal muscle
○
ACh
○
-
Autonomic efferent innervation
Preganglionic neuron and synapses in ganglion with post
ganglionic fiber
Unmyelinated postganglionic fiber (axon)
§
○
Ach or NE
○
-
Comparison of the Somatic and Autonomic Nervous Systems
Feature Somatic Autonomic
Effectors
Skeletal muscles
Glands, smooth
muscle, cardiac
muscles
Control
Usually voluntary
Usually involuntary
Efferent pathways
One nerve fiber from
CNS to effector; no
ganglia
Two nerve fibers
from CNS to
effector; synapse at
ganglion
Distal nerve
endings
Neuromuscular
junctions
Varicosities
Releases
neurotransmitte
r, releases to
numerous cells
-
Neurotransmitters
ACh
ACh and
norepinephrine
(NE)
Effect on target cell
Always excitatory
Excitatory or
inhibitory
Effect of
denervation
Flaccid paralysis
Denervation
hypersensitivity, put
in more receptors to
neurotransmitter,
more sensitive to
them
General Actions of the ANS
Involuntary control of glands, cardiac muscle, and smooth
muscle
Visceral reflexes
○
Unconscious, automatic, responses of visceral effectors to
stimuli
○
Example: a rise in blood pressure triggers a reflexive
decrease in heart rate
○
-
ANS not required for effector activity, but ANS modulates the
activity
Example: heart cells still beat without ANS, innate beating
rate of ~100BPM (intrinsic rate)
○
-
Comparison of sympathetic and parasympathetic division
Sympathetic Division
Thoracolumbar division
Preganglionic somas are in lateral horns of spinal
cord
§
○
Short preganglionic fibers, long postganglionic fibers out
to the target tissues
○
Sympathetic chain ganglia (paravertebral ganglia) from
cervical to coccygeal levels
Chains go all the way to coccyx region
§
○
Sympathetic Pathways (right) compared to somatic
efferent pathways (left)
Both on each side
§
Sympathetic
3 BRANCHES
□
§
Spinal nerve route
Preganglionic neuron going out through spinal
nerve
□
§
Sympathetic nerve route
Synapsing in ganglia
□
Take impulses out to head and thoracic regions
□
§
Splanchnic nerve route
Don't synapse with this one, go all the way
through the ganglia and reach a collateral ganglia
towards the front of the spinal cord
□
§
○
-
Adrenal Glands
Located atop kidneys
-
Adrenal cortex
Outer part
○
Secretes hormones
○
-
Adrenal medulla
Inner part
○
Secretes epinephrine, norepinephrine
○
Resembles a sympathetic ganglion
○
-
The Parasympathetic Division
Craniosacral division
-
Long preganglionic fibers synapses with short postganglionic
fibers
-
Terminal ganglia are in or near target organ
-
Selective in its stimulation of target organs
-
Fibers found within four cranial nerves
CN III Oculomotor nerve controls lens and pupils
○
CN VII Facial nerve controls tear, salivary, nasal glands
○
CN IX Glossopharyngeal nerve controls salivary glands
○
CN X Vagus nerves provides branches for heart, lungs,
esophagus and other organs
Contains about 90% of parasympathetic
preganglionic fibers
§
○
-
Sacral parasympathetic fibers form pelvic splanchnic nerves
-
Comparison of Sympathetic and Parasympathetic division
Feature Sympathetic Parasympathetic
Origin in
CNS
Thoracolumbar Craniosacral
Location
of ganglia
Paravertebral ganglia adjacent to
spinal column and prevertebral
ganglia anterior to it
Terminal ganglia
near or within
target organs
Fiber
lengths
Short preganglionic, long
postganglionic
Long
preganglionic,
short
postganglionic
Neuronal
divergence
Extensive Minimal
Effects of
system
Often widespread and general More local and
specific
Sympathetic and Parasympathetic Branches can be transmitters
by their neurotransmitters and receptors
Both sympathetic and parasympathetic preganglionic neurons
acetylcholine onto cholinergic receptors on postganglionic
neurons
-
Most postganglionic sympathetic neurons secrete
norepinephrine onto adrenergic receptors on the target cells
-
Most postganglionic parasympathetic neurons secrete
acetylcholine onto cholinergic receptors on the target cells
-
Acetylcholine (neurotransmitter)
Acetylcholine secreting cells called "cholinergic" fibers
-
Cells influences by ACh have cholinergic receptors
-
Muscarinic receptors are on involuntary effectors
Mushroom toxin
○
Depending on which type, can be excitatory or inhibitory
○
-
Nicotinic receptors are on postganglionic neurons
Tobacco plant toxins, excitatory on target cells
○
-
Norepinephrine (NE) (neurotransmitter)
Secreting cells called "adrenergic" fibers
-
Secreted by sympathetic postganglionic neurons
-
Cells influenced by NE have adrenergic receptors
Alpha-adrenergic receptors on some effector target cells
Excitatory effect on target cells
§
○
Beta-adrenergic receptors on some effector target cells
Inhibitory effect on target cells
§
○
-
How does it work?
The two divisions can affect body organs different because
their postganglionic neurons release different
neurotransmitters and the effectors possess different
adrenergic (e.g. alpha, beta, with sub types) and
cholinergic (e.g. muscarinic, nicotinic) receptors
○
Different receptors can respond to the same
neurotransmitter with varying affinities
○
There can also be differences in target cell receptor signal
messenger mechanisms
○
Most body organs are innervated by both divisions which
typically work in opposition to each other
Most normal activities
Heart rate
□
Blood flow through tissues
□
Blood pressure
□
Temperature
□
Regulation
□
Water balance
□
§
Duel innervation of the Iris
Most viscera contain fibers from both autonomic
divisions
□
Divisions may have antagonistic or cooperative
effects
□
Antagonistic effect on same cells
□
Cooperative effect on different cells for unified
results
□
Sympathetic allows more light to come in the
eye
□
Parasympathetic restrict the pupil and prevent
light from coming in
□
§
Control without dual innervation
Vasomotor control (blood flow) with more or
less sympathetic nerve impulse
No parasympathetic involvement
®
□
More sympathetic impulses ---> causes
constriction and vasoconstrictor, blood vessel
gets smaller
□
Less impulses ---> blood vessels dilate, relax, get
larger
□
§
○
-
Effects of the Sympathetic and Parasympathetic Nervous
System
Target Effect of
Sympathetic
Division
Effect of
Parasympatheti
c Division
Bronchioles Bronchodilatio
n
Bronchoconstrict
ion
Kidneys Reduced urine
output
No effect
Muscle of bladder wall No effect Contraction,
emptying
bladder
Salivary glands Thick mucous
secretion
Thin serious
secretion
Gastrointestinal motility Decreased Increased
Gastrointestinal secretion Decreased Increased
Liver Glycogen
breakdown
Glycogen
synthesis
Pancreatic enzyme secretion Decreased Increased
Penis and clitoris Loss of
erection
Erection
Ejaculation (smooth muscle
roles-sperm propulsion and
glandular secretion)
Stimulation No effect
Central Controls
Autonomic output originates in CNS
-
The efferent neurons of the autonomic division are closely
linked to homeostatic control centers in the hypothalamus,
pons, and medulla
-
What happens when you swerve to miss hitting a bicyclist?
Increased heart rate and respiratory rate as a result of a
situation you are aware of
○
-
The Enteric (Digestive) Nervous System
Digestive tract has its own nervous system
-
Innervates smooth muscle of gastrointestinal tract and glands
-
Regulates
Motility of the esophagus, stomach, and intestines
○
Secretion of digestive enzymes and acid
○
-
Also controlled by the parasympathetic and sympathetic
division of ANS
-
More activity when you eat something
-
Less activity when you haven't ate anything
-
Chagus Disease
Trpanosoma cruzi destroys autonomic ganglia
-
Bites you, regurgitates into your blood
-
Ganglia are infected, fibers are abnormal
-
Online Lecture - Week 5 (Autonomic Nervous
System)
Friday, April 27, 2018 2:00 PM
Document Summary
Fight or flight responses for increased physical activity. Reduces blood flow to skin and gi tract. Autonomic tone: balance between activity of sympathetic and parasympathetic tone. Comparison of neural pathways of somatic and autonomic. Preganglionic neuron and synapses in ganglion with post ganglionic fiber. Comparison of the somatic and autonomic nervous systems. Two nerve fibers from cns to effector; synapse at ganglion. Denervation hypersensitivity, put in more receptors to neurotransmitter, more sensitive to them. Involuntary control of glands, cardiac muscle, and smooth muscle. Unconscious, automatic, responses of visceral effectors to stimuli. Example: a rise in blood pressure triggers a reflexive stimuli. Example: a rise in blood pressure triggers a reflexive decrease in heart rate. Ans not required for effector activity, but ans modulates the activity. Example: heart cells still beat without ans, innate beating rate of ~100bpm (intrinsic rate) Preganglionic somas are in lateral horns of spinal cord. Short preganglionic fibers, long postganglionic fibers out to the target tissues.
