Chapter 7Chapter 7

The Peripheral Nervous The Peripheral Nervous System: Efferent DivisionSystem: Efferent Division

by Dr. Jay M. Templin

© Brooks/Cole - Thomson Learning

Nervous System

Central PeripheralNervous Nervous

System (CNS) System (PNS)

Brain, Spinal Cord Cranial/SpinalNerves

Peripheral Nervous System

Somatic AutonomicNervous Nervous System System

Consist of cranial Consist of and spinal nerves nerve fibersinnervating innervatingskeletal muscles visceral organs

•Cervical •cord

•Thoracic •cord

•Lumbar •cord

•Sacral •cord

•Vertebrae•Cervical •nerves

•Thoracic •nerves

•Lumbar •nerves

•Sacral •nerves

•Coccygeal•nerve

•Cauda•equina

There are two efferent fibers innervating the effector organ

(visceral organs)

There is only one efferent motor fiber innervating the

effector organ (skeletal muscles)

Efferent fibers release two types of neurotransmitters (see difference between sympathetic and parasympathetic systems)

Motor nerve fibers release acetylcholine which act on

nicotinic Ach receptors

Efferent fibers originate in brain stem or spinal cord

Efferent motor fibers originate in brain stem or spinal cord

Regulate autonomous body functions

Carry motor information out of the NS

Autonomic Nervous SystemSomatic Nervous System

Efferent Outputs

(Brain stem or Spinal cord) (Visceral organ)

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Autonomic Nervous System

Origin of Sympathetic Preganglionic Fibers

in Spinal Cord

Autonomic Nervous System

Sympathetic ParasympatheticSystem System

Mediate fight or Mediate rest or flight responses digest responses

Cholinergic receptors

Adrenergic Receptors

Figure 7.3Page 241

Eye

Nasal mucosa

Sympathetic

Spinal nerves

Sympathetictrunk

Splanchinonerves

Liver

Gallbladder

PancreasAdrenal gland

Kidney

Smallintestine

ColonRectumUrinary bladder

Genitalia

Lung

Heart

Spinalnerves

Cranialnerves

Salivaryglands

Parasympathetic

Parotid gland

Trachea

Lacrimal gland

Stomach

SpleenSympathetic preganglionic fiber

Parasympathetic postganglionicfiber

Parasympathetic preganglionicfiber

Sympathetic postganglionic fiber

Autonomic ganglion is located far from the spinal cord, near the

effector organ

Autonomic ganglion is located near the spinal cord, far from effector

organPostganglionic fibers release acetylcholine

Postganglionic fibers release noradrenaline

Autonomic fibers originate from brain stemand sacral spinal segment

Autonomic fibers originate from thoracic

and lumbar spinal segment

Rest or digest responseFlight or fight response

Parasympathetic System

SympatheticSystem

Autonomic Control of PupillaryReflex

Autonomic Control of Lens: Adaptation

Fight or Flight Response

StressDanger

Increase heart beatsIncrease blood pressure (Vasoconstriction)

Increase air flow into airwaysRelease of glycogen into blood stream

Dilation of skeletal blood vesselsDilation of pupilsIncrease sweating

Down regulation of digestion and urinary activity

Peripheral Nervous System

Somatic AutonomicNervous Nervous System System

Consist of cranial Consist of and spinal nerves nerve fibersinnervating innervatingskeletal muscles 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/clostridia_neurotox/movie/botulinum_movie.html

http://www.pbs.org/wnet/closetohome/animation/gaba-anim2-main.html