Anatomy and Physiology by Rod R Seeley 6th edition chapter 16 power-point

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Anatomy and Physiology, Sixth Edition
Rod R. SeeleyIdaho State University Trent D.
StephensIdaho State University Philip
TatePhoenix College
Chapter 16 Lecture Outline
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Chapter 16

• Autonomic Nervous System

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Somatic and Autonomic Nervous System

• Autonomic
• Smooth and cardiac muscle and glands
• Unconscious regulation
• Target tissues stimulated or inhibited
• Two synapses
• Acetycholine by preganglionic neurons and ACh or
  norepinephrine by postganglionic neurons

• Somatic
• Skeletal muscle
• Conscious and unconscious movement
• Skeletal muscle contracts
• One synapse
• Acetylcholine

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Sympathetic Division

• Preganglionic cell bodies in lateral horns of
  spinal cord T1-L2
• Preganglionic axons pass through ventral roots to
  white rami communicantes to sympathetic chain
  ganglia
• Four routes possible
• Spinal nerves
• Sympathetic nerves
• Splanchnic nerves
• Innervation to adrenal gland

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Routes by Sympathetic Axons
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Parasympathetic Division

• Preganglionic cell bodies in nuclei of brainstem
  or lateral parts of spinal cord gray matter from
  S2-S4
• Preganglionic axons from brain pass to ganglia
  through cranial nerves
• Preganglionic axons from sacral region pass
  through pelvic nerves to ganglia
• Preganglionic axons pass to terminal ganglia
  within wall of or near organ innervated

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Enteric Nervous System

• Consists of nerve plexuses within wall of
  digestive tract
• Sources
• Sensory neurons that connect the digestive tract
  to CNS
• ANS motor neurons that connect CNS to digestive
  tract
• Enteric neuron which are confined to enteric
  plexuses

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Distribution of ANS Fibers

• Sympathetic axons reach organs through
• Spinal nerves
• Head and neck nerve plexuses
• Thoracic nerve plexuses
• Abdominopelvic nerve plexuses
• Parasympathetic axons reach organs through
• Cranial nerves
• Thoracic nerve plexuses
• Abdominopelvic nerve plexuses
• Pelvic nerves

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Physiology of ANS

• Neurotransmitters
• Acetylcholine released by cholinergic neruons
• Norepinephrine released by adrenergic neurons
• Receptors
• Cholinergic
• Nicotinic and muscarinic
• Adrenergic
• Alpha and beta receptors

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Location of ANS Receptors
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Regulation of ANS

• Autonomic reflexes control most of activity of
  visceral organs, glands, and blood vessels
• Autonomic reflex activity influenced by
  hypothalamus and higher brain centers
• Sympathetic and parasympathetic divisions
  influence activities of enteric nervous system
  through autonomic reflexes
• Enteric nervous system can function independently
  of CNS through local reflexes

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Autonomic Reflexes
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Influence of Brain on Autonomic Functions
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Functional Generalizations of ANS

• Stimulatory versus inhibitory effects
• Both divisions of ANS
• Dual innervation
• Most organs innervated by both
• Either division alone or both working together
  can coordinate activities of different structures
• Sympathetic produces more generalized effects
• Prepares body for physical activity or
  flight-or-fight response
• Parasympathetic more important for resting
  conditions
• SLUDD Salivation, lacrimation, urination,
  digestion, defecation

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Fight-or-Flight Responses

• Increased heart rate and force
• Blood vessel dilation in skeletal and cardiac
  muscles
• Dilation of air passageways
• Energy sources availability increased
• Glycogen to glucose
• Fat cells break down triglycerides
• Muscles generate heat, body temperature increases
• Sweat gland activity increases
• Decrease in nonessential organ activities