Chapter 7
The Peripheral Nervous
System: Efferent Division
by Dr. Jay M. Templin
© Brooks/Cole - Thomson Learning
Nervous System
Central
Nervous
System (CNS)
Brain, Spinal Cord
Peripheral
Nervous
System (PNS)
Cranial/Spinal
Nerves
Peripheral Nervous System
Somatic
Nervous
System
Consist of cranial
and spinal nerves
innervating
skeletal muscles
Autonomic
Nervous
System
Consist of
nerve fibers
innervating
visceral organs
•Cervical
•cord
•Cervical
•nerves
•Thoracic
•cord
•Thoracic
•nerves
•Lumbar
•cord
•Sacral
•cord
•Lumbar
•nerves
•Sacral
•nerves
•Coccygeal
•nerve
•Vertebrae
•Cauda
•equina
Autonomic Nervous System
Somatic
Nervous System
Carry motor information out
Regulate autonomous body
of the NS
functions
Efferent motor fibers originate
Efferent fibers originate in
in brain stem or spinal cord
brain stem or spinal cord
There is only one efferent
There are two efferent fibers
motor fiber innervating the
innervating the effector organ
effector organ (skeletal
(visceral organs)
muscles)
Motor nerve fibers release
Efferent fibers release two
acetylcholine which act on
types of neurotransmitters (see
nicotinic Ach receptors
difference between sympathetic
and parasympathetic systems)
Efferent Outputs
(Brain stem or Spinal cord)
(Visceral organ)
© Brooks/Cole - Thomson Learning
Autonomic Nervous System
Origin of Sympathetic
Preganglionic Fibers
in Spinal Cord
Autonomic Nervous System
Sympathetic
System
Parasympathetic
System
Mediate fight or
flight responses
Mediate rest or
digest responses
Cholinergic receptors
Adrenergic Receptors
Eye
Lacrimal gland
Parotid gland
Nasal mucosa
Sympathetic
Salivary
glands
Spinal
nerves
Sympathetic
trunk
Liver
Splanchino
nerves
Adrenal
gland
Parasympathetic
Figure
7.3
Page 241
Trachea
Lung
Heart
Stomach
Gall
bladder
Pancreas
Spleen
Genitalia
Sympathetic preganglionic fiber
Sympathetic postganglionic fiber
Spinal
nerves
Kidney
Small
intestine
Cranial
nerves
Colon
Rectum
Urinary bladder
Parasympathetic preganglionic
fiber
Parasympathetic postganglionic
fiber
Sympathetic
System
Parasympathetic
System
Flight or fight response
Rest or digest response
Autonomic fibers
originate from thoracic
and lumbar spinal
segment
Autonomic ganglion is
located near the spinal
cord, far from effector
organ
Postganglionic fibers
release noradrenaline
Autonomic fibers
originate from brain stem
and sacral spinal segment
Autonomic ganglion is
located far from the
spinal cord, near the
effector organ
Postganglionic fibers
release acetylcholine
Autonomic Control of Pupillary
Reflex
Autonomic Control of Lens:
Adaptation
Fight or Flight Response
Stress
Danger
Increase heart beats
Increase blood pressure (Vasoconstriction)
Increase air flow into airways
Release of glycogen into blood stream
Dilation of skeletal blood vessels
Dilation of pupils
Increase sweating
Down regulation of digestion and urinary activity
Peripheral Nervous System
Somatic
Nervous
System
Consist of cranial
and spinal nerves
innervating
skeletal muscles
Autonomic
Nervous
System
Consist of
nerve fibers
innervating
visceral organs
Motor Unit: consist of all muscle
fibers innervated by one motor
neuron
Neuromuscular Junction
© Brooks/Cole - Thomson Learning
Neuromuscular Junction
http://www.blackwellpublishing.com/matthews/nmj.html
http://www.toppermost.biz/Junction.html
http://www.microvet.arizona.edu/Courses/MIC420/lecture_notes/clostridia/clostri
dia_neurotox/movie/botulinum_movie.html
http://www.pbs.org/wnet/closetohome/animation/gaba-anim2-main.html