Download The Nervous System: Neural Tissue

Chapter
13
The Nervous
System: Neural
Tissue
PowerPoint® Lecture Slides
prepared by Jason LaPres
North Harris College
Houston, Texas
Copyright © 2009 Pearson Education, Inc.,
publishing as Pearson Benjamin Cummings
Introduction
 Nervous system and endocrine system
 Control and adjust the activities of other systems
 Shared characteristics:
 Chemical communication with targeted tissues
 Nervous system
 Relatively swift but brief responses
 Endocrine
 Slower but they often last much longer
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An Overview of the Nervous System
 The nervous system = all of the neural tissue
 Two anatomical subdivisions:
 Central nervous system (CNS)
 Brain and spinal cord
 Integrating, processing, and coordinating
 Intelligence, memory, learning, and emotion
 Peripheral nervous system (PNS)
 Neural tissue outside the CNS
 Provides sensory information to the CNS
 Carries motor commands to peripheral tissues
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
An Overview of the Nervous System
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
An Overview of the Nervous System
Figure 13.1
The Nervous System
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
An Overview of the Nervous System
The PNS is subdivided into two divisions.
 The afferent division of the PNS brings sensory
information to the CNS.
 The efferent division carries motor commands to
muscles and glands.
 The efferent division is further divided into two
divisions:
 Somatic nervous system (SNS)
 Autonomic nervous system (ANS)
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
An Overview of the Nervous System
Afferent division
 Receptors
The afferent division carries information from
 Somatic sensory receptors
 Skeletal muscles, joints, and the skin
 Visceral sensory receptors
 Smooth muscle, cardiac muscle, and glands
 Special sense organs
 Eye, nose, tongue, and ear
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
An Overview of the Nervous System
 The efferent division begins inside the CNS and ends
at an effector.
 The efferent division
 Somatic nervous system (SNS)
 Skeletal muscle contractions
 May be voluntary or involuntary
 Autonomic nervous system (ANS)
 Visceral motor system
 Smooth muscle, cardiac muscle, and glands
 Involuntary
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An Overview of the Nervous System
Figure 13.2
A Functional Overview of the Nervous System
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Cellular Organization in Neural Tissue
 Neural tissue contains two distinct cell types: nerve cells,
or neurons, and supporting cells, or neuroglia.
 Neurons are responsible for the transfer and processing of
information in the nervous system.
 Supporting cells, or neuroglia, isolate the neurons.
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Cellular Organization in Neural Tissue
Figure 13.3
A Review of Neuron Structure
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M
Cellular
Organization in Neural Tissue
Neuron Structure
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Cellular Organization in Neural Tissue
 Neuroglia have many functions, including:
 Provide framework for the neural tissue
 Maintain the intercellular environment
 Act as phagocytes
 100 billion neuroglia, or glial cells
 Roughly five times the number of neurons
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Cellular Organization in Neural Tissue
Figure 13.4
The Classification of Neuroglia
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Cellular Organization in Neural Tissue
Figure 13.5
Histology of Neural Tissue in the CNS
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Cellular Organization in Neural Tissue
 Astrocytes
 Largest and most numerous glial cells
 Variety of functions
 Controlling the interstitial environment
 Maintaining the blood–brain barrier
 Creating a three-dimensional framework for the CNS
 Performing repairs in damaged neural tissue
 Guiding neuron development
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Cellular Organization in Neural Tissue
Figure 13.6
The Ependyma
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Cellular Organization in Neural Tissue
Figure 13.7
Satellite Cells and Peripheral Neurons
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Cellular Organization in Neural Tissue
Figure 13.8
Schwann Cells and Peripheral Axons
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Cellular Organization in Neural Tissue
Figure 13.9
Anatomy of a Representative Neuron (Diagrammatic)
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Cellular Organization in Neural Tissue
Figure 13.10
A Structural Classification of Neurons
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Cellular Organization in Neural Tissue
 Neurons can be categorized into three functional
groups:
 Sensory neurons
 Most sensory neurons are pseudounipolar neurons
 Motor neurons
 Most motor neurons are multipolar neurons
 Interneurons, or association neurons
 Most interneurons are multipolar neurons
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Cellular Organization in Neural Tissue
 Receptors are monitored by the sensory neurons
 Exteroceptors = external environment
 Touch, temperature, and pressure sensations
 Special senses of sight, smell, and hearing
 Proprioceptors = internal environment
 Position and movement of skeletal muscles and joints
 Information carried in somatic sensory neurons
 Interoceptors = internal environment
 Digestive, respiratory, cardiovascular, urinary, and reproductive
systems
 Sensations of deep pressure and pain as well as taste
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Cellular Organization in Neural Tissue
Figure 13.11
A Functional Classification of Neurons
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Neural Regeneration
Figure 13.12
Nerve Regeneration after Injury
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The Nerve Impulse
 Excitability is the ability of a plasmalemma to
conduct electrical impulses.
An electrical impulse, or action potential, develops
after the plasmalemma is stimulated to its threshold.
Nerve impulse is an action potential traveling along an
axion.
The rate of impulse conduction depends on the properties
of the axon, specifically:
 Presence or absence of myelin sheath
 The diameter
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Synaptic Communication
Figure 13.9
Anatomy of Representative Neuron (Synapses Shown)
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Synaptic Communication
Figure 13.13a
The Structure of a Synapse (A Vesicular Synapse)
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Synaptic Communication
Figure 13.13b
The Structure of a Synapse (On The Surface of a Neuron)
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Neuron Organization and Processing
Figure 13.14
Organization of Neural Circuits
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Anatomical Organization of the Nervous System
Figure 13.15
Anatomical Organization of the Nervous System
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Anatomical Organization of the Nervous System
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings