biology
nwaf
reflexes-110608164056-phpapp02.ppt
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
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
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
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
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
