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C h a p t e r
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
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
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
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
An Overview of the Nervous System
Figure 13.2 A Functional Overview of the Nervous System
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
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.
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Cellular Organization in Neural Tissue
Figure 13.3 A Review of Neuron Structure
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M
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Cellular Organization in Neural Tissue
Neuron Structure
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
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Cellular Organization in Neural Tissue
Figure 13.4 The Classification of Neuroglia
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Cellular Organization in Neural Tissue
Figure 13.5 Histology of Neural Tissue in the CNS
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
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 AxonsCopyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Cellular Organization in Neural Tissue
Figure 13.9 Anatomy of a Representative Neuron (Diagrammatic)
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Cellular Organization in Neural Tissue
Figure 13.10 A Structural Classification of Neurons
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
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
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
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)
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Synaptic Communication
Figure 13.13a The Structure of a Synapse (A Vesicular Synapse)
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Synaptic Communication
Figure 13.13b The Structure of a Synapse (On The Surface of a Neuron)
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
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
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Anatomical Organization of the Nervous System
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
