Transcript PNS & ANS - Orange Coast College

Essentials of Anatomy and Physiology
Fifth edition
Seeley, Stephens and Tate
Chapter 8: Nervous System
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 2.1
Spinal Nerves
 31 pairs, each arising from a spinal
segment
 Spinal nerves are all MIXED nerves
Named for the vertebral level from
which they arise
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.63
Spinal Nerves
Figure 7.22a
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Slide 7.64
Autonomic Nervous System
 The involuntary component of the
nervous system
 Consists of only motor nerves
 Divided into two divisions
 Sympathetic division
 Parasympathetic division
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.67
Autonomic Nervous System
 Sympathetic division
 “Fight or Flight” response
 Specialized to act in emergencies
 Short acting
 Long term activation leads to “stress
disorders”
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.67
Autonomic Nervous System
 Parasympathetic division
 “Rest and Repose” system
 Specialized to return body to homeostasis
 Long acting
 Where the body is “supposed” to be
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.67
Differences Between Somatic and
Autonomic Nervous Systems
 Neurotransmitters
 Somatic – always use acetylcholine
 Autonomic – use acetylcholine,
epinephrine, or norepinephrine
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.68b
Anatomy of the Autonomic Nervous
System
Figure 7.25
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Slide 7.73
Autonomic Functioning
 Sympathetic – “fight-or-flight”
 Response to unusual stimuli
 Takes over to increase specific activities
 The “E” ticket = exercise, excitement,
emergency, and embarrassment
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.74a
Autonomic Functioning
 Parasympathetic – housekeeping
activities
 Conserves energy
 Maintains daily necessary body functions
 The “D” division - digestion, defecation, and
diuresis (urination)
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.74b
Neurotransmitters
 Excitatory: facilitate transmission
Acetylcholine
Epinephrine and norepinephrine
Amino acids:
Aspartate: spinal cord
Glutamate: cerebral cortex,
brainstem
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.74b
Neurotransmitters
 Inhibitory: inhibit transmission
GABA
Serotonin (SSRI’s, i.e., prozac, etc.)
Dopamine (cocaine, meth)
Histamine
 Endorphins
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.74b
Development Aspects of the
Nervous System: FYI
 The nervous system forms during the
first month of embryonic development
 Any maternal infection, chemical use, or
radiation exposure can have harmful
effects
 The hypothalamus is one of the last
areas of the brain to develop
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.75a
Development Aspects of the
Nervous System: FYI
 Very few neurons are formed after birth
 growth and maturation continue for years
 additional pathways are formed
 The brain reaches maximum weight as
a young adult
 As we age, “use it or lose it”!!
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.75b