Classification of the Nervous System

Brain Central nervous system (CNS) Spinal cord Peripheral (PNS) Afferent division Efferent Sensory stimuli Visceral Somatic nervous system Autonomic Motor neurons Sympathetic Parasympathetic Skeletal muscle Smooth muscle Cardiac muscle Glands Effector organs (made up of muscle and gland tissue) (Input to CNS from periphery) (Output from CNS to periphery)

Classification We can divide the nervous system using many different sets of terminology… Anatomical Direction of Impulses Functional

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 System 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 Slide 7.1a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Structural Classification of the Nervous System Central nervous system (CNS) Brain Spinal cord Peripheral nervous system (PNS) Nerve outside the brain and spinal cord Slide 7.2 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Functional Classification of the Peripheral Nervous System Sensory (afferent) division Nerve fibers that carry information to the central nervous system Figure 7.1 Slide 7.3a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Functional Classification of the Peripheral Nervous System Motor (efferent) division Nerve fibers that carry impulses away from the central nervous system Figure 7.1 Slide 7.3b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Functional Classification of the Peripheral Nervous System Motor (efferent) division Two subdivisions Somatic nervous system = voluntary Autonomic nervous system = involuntary Figure 7.1 Slide 7.3c Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Organization of the Nervous System Figure 7.2 Slide 7.4 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

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Central Nervous System:

Central Nervous System: Consists of Brain Located in cranial vault of skull Spinal cord Located in vertebral canal Brain and spinal cord Continuous with each other at foramen magnum

Peripheral Nervous System: comprises peripheral nerves (cranial & spinal) & ganglia Two subcategories Sensory or afferent (input) Motor or efferent (output) Divisions Somatic nervous system Autonomic nervous system (ANS) Sympathetic Parasympathetic Enteric

PNS Cranial Nerves

PNS Spinal Nerves Ganglia