The Nervous System

/in /by

ELAINE N. MARIEB

EIGHTH EDITION

7

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

PowerPoint® Lecture Slide Presentation by Jerry L. Cook, Sam Houston University

ESSENTIALS

OF HUMAN

ANATOMY

& PHYSIOLOGY

The Nervous System

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Functional Classification of Neurons

Sensory (afferent) neurons
Carry impulses from the sensory receptors
Cutaneous sense organs
Motor (efferent) neurons
Carry impulses from the central nervous system
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Functional Classification of Neurons

Interneurons (association neurons)
Found in neural pathways in the central nervous system
Connect sensory and motor neurons
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Neuron Classification

Figure 7.6

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The Reflex Arc

Reflex – rapid, predictable, and involuntary responses to stimuli
Reflex arc – direct route from a sensory neuron, to an interneuron, to an effector
Figure 7.11a

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Simple Reflex Arc

Figure 7.11b–c

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Types of Reflexes and Regulation

Autonomic reflexes
Smooth muscle regulation
Heart and blood pressure regulation
Regulation of glands
Digestive system regulation
Somatic reflexes
Activation of skeletal muscles
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Autonomic Reflexes

Abdominal Reflex
Stimulus: light stroking of the abdomen
Response: Contraction of the abdominal muscles that pull navel towards stimulus
Spinal Segment: T7 – T12
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Somatic Reflexes

Biceps Reflex
Stimulus: tap to tendon of biceps brachii muscle
Response: Flexion at elbow
Spinal Segment: C5, C6
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Somatic Reflexes

Triceps Reflex
Stimulus: Tap to tendon of triceps brachii muscle
Response: Extension at elbow
Spinal Segment: C6, C7
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Somatic Reflexes

Patellar Reflex
Stimulus: tap to patellar tendon
Response: extension at knee
Spinal Segment: L2-L4
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Somatic Reflexes

Ankle-jerk Reflex
Stimulus: Tap to calcaneal tendon
Response: extension (plantar flexion) at ankle
Spinal Segment: S1-S2