Classification of the Nervous System

Brain

Centralnervoussystem(CNS)

Spinalcord

Peripheralnervoussystem(PNS)

Afferentdivision

Efferentdivision

Sensorystimuli

Visceralstimuli

Somaticnervous system

Autonomicnervous system

Motor neurons

Sympatheticnervous system

Parasympatheticnervous system

Skeletal muscle

Smooth muscleCardiac muscleGlands

Effector organs(made up of muscle and gland tissue)

(Input to CNSfrom periphery)

(Output from CNSto periphery)

ClassificationWe can divide the nervous system using many different sets of terminology…

Anatomical Direction of ImpulsesFunctional

Lets just keep it simple…Central Nervous System

Peripheral Nervous System

Stimulus NS Response

Input NS Output

More complex features of the NS:intellect, consciousness, emotions, motivation, association, memory, language …….

Functions of the Nervous SystemFunctions of the Nervous System

Slide 7.1aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

1. Sensory input – gathering information To monitor changes occurring inside and

outside the body (changes = stimuli)

2. Integration – to process and interpret sensory input

and decide if action is needed.

3. Motor output

A response to integrated stimuli

The response activates muscles or glands

Structural Classification of the Structural Classification of the Nervous SystemNervous System

Slide 7.2Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Central nervous system (CNS)

Brain

Spinal cord

Peripheral nervous system (PNS)

Nerve outside the brain and spinal cord

Functional Classification of the Functional Classification of the Peripheral Nervous SystemPeripheral Nervous System

Slide 7.3aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Sensory (afferent) division

Nerve fibers that carry information to the central nervous system

Figure 7.1

Functional Classification of the Functional Classification of the Peripheral Nervous SystemPeripheral Nervous System

Slide 7.3bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Motor (efferent) division

Nerve fibers that carry impulses away from the central nervous system

Figure 7.1

Functional Classification of the Functional Classification of the Peripheral Nervous SystemPeripheral Nervous System

Slide 7.3cCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Motor (efferent) division Two subdivisions

Somatic nervous system = voluntary Autonomic nervous system = involuntary

Figure 7.1

Organization of the Nervous Organization of the Nervous SystemSystem

Slide 7.4Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 7.2

Central Nervous System:

Consists ofBrainLocated in cranial

vault of skull

Spinal cordLocated in vertebral

canal

Brain and spinal cord

Continuous with each other at foramen magnum

Central Nervous System:

Peripheral Nervous System:comprises peripheral nerves (cranial &

spinal)& ganglia Two subcategories

Sensory or afferent (input)Motor or efferent (output)

DivisionsSomatic nervous systemAutonomic nervous system (ANS)

Sympathetic ParasympatheticEnteric

PNS

Cranial Nerves

PNS

Spinal Nerves

Ganglia