Download Chapter 18-Autonomic Nervous System

Co 18
Chapter 18
Autonomic
Nervous
System
Fig. 18.1
Somatic Nervous System
Somatic Nervous System
Posterior root ganglion
Anterior root
Somatic motor neuron
sends nerve impulses to
skeletal muscle.
Somatic sensory
neuron detects stimuli
and transmits nerve
impulses from skin,
skeletal muscle, joints,
and special senses
(vision, hearing, etc.).
Skeletal muscle Sensory receptor
in skin
(a)
• Sends stimuli from vision,
hearing, equilibrium, smell,
taste, touch, proprioception to
CNS
• Carries voluntary (conscious
and unconscious) nerve
impulses for skeletal muscle
control
Fig. 18.1
Autonomic Nervous System
• AKA visceral nervous
system
• Works reflexively and
without awareness
• Visceral sensory
components sense
stimuli from blood
vessels and internal
organs
• Autonomic motor
components transmit
nerve impulses to cardiac
muscle, smooth muscle,
and glands
Autonomic Nervous System
Autonomic
ganglion
Preganglionic autonomic motor neuron transmits
nerve impulses to a ganglionic motor neuron.
Ganglionic autonomic
motor neuron transmits
Visceral sensory
nerve impulses to smooth
neuron detects
muscle, cardiac muscle,
stimuli within blood
and glands.
vessels and smooth
muscle in the
Smooth muscle
viscera.
in trachea
Sensory receptor
in viscera
(b)
Fig. 18.2 Lower Motor Neurons of Autonomic Nervous System
• Preganglionic neuron extends from brainstem or spinal
cord, axon exits CNS in cranial or spinal nerve
• Autonomic ganglion is where pre- and post-ganglionic
neurons synapse; houses ganglionic neuron cell body
• Ganglionic neuron cell body attached to postganglionic axon
Autonomic ganglion
Postganglionic axon
Preganglionic axon
Preganglionic neuron cell body
Spinal cord
Ganglionic neuron cell body
Effector organ (e.g., cardiac
muscle, smooth muscle, or
gland)
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Page 540
1 “Preganglionic” flight from Indianapolis
to Chicago (autonomic ganglion)
Chicago
Indianapolis
• Two-neuron system enables more
complex signaling and better
control
• Neuronal convergence and
neuronal divergence
Miami
2 “Postganglionic” flight
from Chicago to Miami
(effector organ)
Sympathetic vs. Parasympathetic
Divisions of Autonomic Nervous System
Sympathetic
• Fight-or-flight response
– increased heart rate and
blood pressure, decreased
digestion
Parasympathetic
• Rest-and-digest response
– decreased heart rate and
blood pressure, increased
digestion
6
Overview of
Parasympathetic
Pathways
Figure 18.5
Overview of
Sympathetic
Pathways
Sympathetic
trunk ganglia
Figure 18.6