Download Neural Integration 2

Fundamentals of
Anatomy & Physiology
SIXTH EDITION
Chapter 16, part 1
Neural Integration II:
The Autonomic Nervous System and
Higher Order Functions
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Central Nervous System Overview
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Learning Objectives
• Compare the organization of the autonomic
nervous system with the somatic nervous system.
• Describe the structures and functions of the
sympathetic and parasympathetic divisions of the
ANS.
• Describe the mechanisms of neurotransmitter
release in the sympathetic and parasympathetic
divisions.
• Describe the effects of sympathetic and
parasympathetic neurotransmitters on target
organs and tissues.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Learning Objectives
• Describe the hierarchy of interacting levels of
control in the ANS
• Explain how memories are created, stored and
recalled.
• Summarize the effects of aging on the nervous
system.
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SECTION 16-1
An Overview of the ANS
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ANS
• Coordinates cardiovascular, respiratory,
digestive, urinary and reproductive functions
• Preganglionic neurons in the CNS send axons to
synapse on ganglionic neurons in autonomic
ganglia outside the CNS
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Divisions of the ANS
• Sympathetic division (thoracolumbar, “fight or
flight”)
• Thoracic and lumbar segments
• Parasympathetic division (craniosacral, “rest and
repose”)
• Preganglionic fibers leaving the brain and
sacral segments
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Sympathetic and Parasympathetic Systems
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SECTION 16-2
The Sympathetic Division
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Sympathetic division anatomy
• Preganglionic neurons between segments
T1 and L2
• Ganglionic neurons in ganglia near
vertebral column
• Specialized neurons in adrenal glands
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Figure 16.3 The Organization of the
Sympathetic Division of the ANS
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Figure 16.3
Sympathetic ganglia
• Sympathetic chain ganglia (paravertebral
ganglia)
• Collateral ganglia (prevertebral ganglia)
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Figure 16.5 The Distribution of Sympathetic
Innervation
PLAY
Animation: The sympathetic division
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Figure 16.5
Sympathetic activation
• In crises, the entire sympathetic division
responds
• Sympathetic activation
• Affects include increased alertness, energy and
euphoria, increased cardiovascular and
respiratory activities, elevation in muscle tone,
mobilization of energy resources
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Neurotransmitters and sympathetic function
• Stimulation of sympathetic division has two
distinct results
• Release of ACh or NE at specific locations
• Secretion of E and NE into general circulation
• Most postganglionic fibers are adrenergic, a few
are cholinergic or nitroxidergic
• Two types of receptors are alpha receptors and
beta receptors
• Sympathetic ganglionic neurons end in
telodendria studded with varicosities filled with
neurotransmitter
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Figure 16.6 Sympathetic Variosities
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Figure 16.6
SECTION 16-3
The Parasympathetic Division
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Parasympathetic division
• Preganglionic neurons in the brainstem and
sacral segments of spinal cord
• Ganglionic neurons in peripheral ganglia located
within or near target organs
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Figure 16.7 The Organization of the
Parasympathetic Division of the ANS
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Figure 16.7
Figure 16.8 The Distribution of Parasympathetic
Innervation
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Figure 16.8
Parasympathetic activation
• Effects produced by the parasympathetic division
• relaxation
• food processing
• energy absorption
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Neurotransmitters and parasympathetic
functions
• All parasympathetic fibers release ACh
• Short-lived response as ACH is broken down by
AChE and tissue cholinesterase
• Postsynaptic membranes have two kinds of
receptors
• Muscarinic
• Nicotinic
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SECTION 16-4
Interactions Between the Sympathetic and
Parasympathetic Divisions
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Sympathetic and parasympathetic divisions
• Sympathetic
• Widespread influence on visceral and somatic
structures
• Parasympathetic
• Innervates only visceral structures serviced by
cranial nerves or lying within the
abdominopelvic cavity
• Dual innervation = organs that receive input
from both systems
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Comparison of the two divisions
• Important physiological and functional
differences exist
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Figure 16.10 Summary: The Anatomical
Differences between the Sympathetic and
Parasympathetic Divisions
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Figure 16.10
SECTION 16-5
Integration and Control of Autonomic Functions
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Higher levels of autonomic control
• Activity in the ANS is controlled by centers in the
brainstem that deal with visceral functioning
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Figure 16.12 Levels of Autonomic Control
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Figure 16.12
SNS and ANS organized in parallel
• Integration occurs at the brainstem and higher
centers
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Figure 16.13 A Comparison of Somatic and
Autonomic Function
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Figure 16.13
SECTION 16-6
High Order Functions
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Higher order functions
• Are performed by the cerebral cortex and involve
complex interactions
• Involve conscious and unconscious information
processing
• Are subject to modification and adjustment over time
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Memory
• Short term or long term
• Memory consolidation is moving from short term to long
term
• Amnesia is the loss of memory due to disease or trauma
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Figure 16.14 Memory Storage
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Figure 16.14
Consciousness
• Deep sleep, the body relaxes and cerebral cortex activity
is low
• REM sleep active dreaming occurs
• The reticular activating system (RAS) is important to
arousal and maintenance of consciousness
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Figure 16.16 The Reticular Activating System
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Figure 16.16
SECTION 16-7
Brain Chemistry and Behavior
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Neurotransmitters and the brain
• Neurotransmitters and brain function
• Changes in balance between neurotransmitters
can profoundly alter brain function
• Personality and self-awareness
• Characteristics of the brain as an integrated
system rather than one specific component
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SECTION 16-8
Aging and the Nervous System
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Age-related changes
•
•
•
•
•
Reduction in brain size and weight
Reduction in the number of neurons
Decrease in blood flow to the brain
Changes in synaptic organization of the brain
Intracellular and extracellular changes in CNS neurons
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
You should now be familiar with:
• The organization of the autonomic nervous system.
• The structures and functions of the sympathetic
and parasympathetic divisions of the ANS.
• The mechanisms of neurotransmitter release in the
sympathetic and parasympathetic divisions.
• The effects of sympathetic and parasympathetic
neurotransmitters on target organs and tissues.
• The hierarchy of interacting levels of control in the
ANS.
• How memories are created, stored and recalled.
• The effects of aging on the nervous system.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings