Download Unit 10 - Perry Local Schools

Unit 10
Autonomic Nervous System (ANS)
Objectives:
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
Comparison of Somatic & Autonomic Nervous
Systems
Structure of the Autonomic Nervous System

Anatomical Components
Functions of the Somatic and Autonomic Nervous Systems
http://study.com/academy/lesson/functions-of-the-somaticautonomic-nervous-systems.html
Comparison: SomaticNS vs AutonomicNS
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SNS
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Controls skeletal muscle
Conscious, voluntary
control
Motor pathway: one neuron
from CNS to effector
Does include sensory
neurons (from skin, skeletal
muscles, and special sense
organs)
All release the
neurotransmitter ACh
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ANS

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Controls viscera: smooth
and cardiac muscle, and
glands
Unconscious, involuntary
Motor pathway: series of
two neurons from CNS to
effector
Does include sensory
neurons (monitors viscera)
Two divisions: sympathetic,
parasympathetic
Release either ACh or NE
Somatic Nervous System
Copyright 2010, John Wiley & Sons, Inc.
Introduction to the ANS
Somatic nervous system (SNS) + ANS 
peripheral nervous system (PNS)
ANS
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Is regulated by hypothalamus, brainstem
The ANS supplies nerves to viscera
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Smooth muscle (stomach, blood vessels)
Cardiac muscle (heart)
Glands (sweat and digestive glands)
ANS Motor Pathways
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Autonomic motor pathway includes two motor
neurons
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CNS  (Autonomic ganglion) Preganglionic 
Postganglionic neuron  to effector
Autonomic Nerve Fibers
11-61
Copyright 2010, John Wiley & Sons, Inc.
Autonomic Nervous System
Two Divisions
• Sympathetic – prepares body for fight or flight situations
• Parasympathetic – prepares body for resting and
digesting activities
Divisions of the ANS
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Sympathetic (S) + parasympathetic (P)
Most viscera supplied with nerves of both S and P
divisions: dual innervation
S and P have opposite (antagonistic) effects
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Heart rate: S stimulates, P inhibits
Digestive organs: S inhibit, P stimulate
Some viscera receive only S (not P) nerves:
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Sweat glands, many blood vessels, hair muscles
Control of Autonomic Activity
Largely CNS
1. Medulla oblongata
• cardiac, vasomotor and respiratory activities
2. Hypothalamus
• regulates balance between sympathetic and
parasympathetic activity
• visceral functions
3. Limbic system & cerebral cortex
• emotional responses
https://www.youtube.com/watch?v=qqU-VjqjczE
11-70
ANS Motor Pathways
Copyright 2010, John Wiley & Sons, Inc.
Objectives:


Organization of the Sympathetic Division
Organization of the Parasympathetic Division
Sympathetic (S) Preganglionic
Cell bodies located in lateral gray of spinal cord
segments T1-T12 + L1-L2
 called “thoracolumbar”
Axons pass through ventral roots of spinal nerves
 May branch many times
 May ascend or descend (from cervical to sacral)
 Can synapse with 20 or more postganglionic cell
bodies
 Results: widespread effects (viscera respond with
one another)
Sympathetic Division
11-62
Copyright 2010, John Wiley & Sons, Inc.
Sympathetic (S) Postganglionic
Cell bodies located
 “Trunk ganglia”
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2 long chains lateral to vertebrae
“Prevertebral ganglia”
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Anterior to 3 large abdominal arteries
“Trunk ganglia”
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From cervical to sacral regions 
widespread effects
Many axons pass back into spinal nerves to
reach skin
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sweat glands, hair muscles, blood vessels
“Prevertebral ganglia”
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Named celiac, superior and inferior
mesenteric ganglia
Supply abdominal viscera: stomach, intestine,
kidneys, liver, spleen
Axons pass from ganglia to viscera in S nerves
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Sympathetic Division
11-63
Copyright 2010, John Wiley & Sons, Inc.
Sympathetic Division
11-64
Copyright 2010, John Wiley & Sons, Inc.
Parasympathetic (P) Preganglionic
Cell bodies located in brainstem + in spinal cord
segments S2-S4
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“Craniosacral”
Parasympathetic Preganglionic
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Axons in cranial nerves III, VII, IX and X and in pelvic
nerves from S2-S4
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Vagus nerves (cranial nerves X) carry 80% of all P nerve
impulses.
Vagus nerves carry both motor and sensory neurons
to/from viscera within the thorax and most of the
abdominal cavity.
Axons do not branch or pass though S trunk ganglia but
pass directly almost to viscera
Parasympathetic Division
11-66
Copyright 2010, John Wiley & Sons, Inc.
Parasympathetic (P) Postganglionic
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Cell bodies lie in terminal ganglia
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Located within or near the innervated organ
cause precise, localized (not widespread) effects
S nerves supply all viscera but P nerves do not
reach some
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sweat glands, arrector pili muscles, kidneys, spleen,
adrenal medullae, and the walls of most blood vessels.
Axons pass from ganglia to viscera in P nerves
Parasympathetic (P) Division
Copyright 2010, John Wiley & Sons, Inc.
Objectives:

Functions of the Autonomic Nervous System
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ANS Neurotransmitters
Activities of the ANS
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Sympathetic Activities
Parasympathetic Activities
ANS Neurotransmitters: Comparison
Acetylcholine (ACh)
 More common
 Released by:
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All S and P preganglionic
axons
All P postganglionic axons
Some S postganglionic
axons (to sweat glands)
Destroyed by enzyme
ACh-ase
Short-lived response
Norepinephrine (NE)
 Less common
 Released by:
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Almost all S postganglionic
axons
Longer lasting effects
Enhanced by epinephrine +
NE from adrenal medullae
Sympathetic Effects
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Fight-or-flight activities
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Increase heart rate and contraction, and blood pressure
(BP)
Dilate pupils
Dilate airways
Dilate vessels to skeletal muscles, heart, liver and
adipose tissue
Constrict blood vessels to nonessential organs: skin, GI
tract, kidneys
Mobilize nutrients for energy: glucose and fats
http://study.com/academy/lesson/fight-or-flightresponse.html
Parasympathetic Effects
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Rest-and-digest activities
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SLUDD
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Salivation
Lacrimation
Urination
Digestion
Defecation
Decrease
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Heart rate,
Airway diameter,
Pupil diameter
Aging and Autonomic Nervous System
http://study.com/academy/lesson/how-age-affects-our-autonomicnervous-system-changes-examples.html