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Essentials of Anatomy and Physiology
Fifth edition
Seeley, Stephens and Tate
Chapter 8: Nervous System
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 2.1
The Reflex Arc
 Reflex – rapid, involuntary responses to
stimuli
 Reflex arc –One kind of conduction
pathway
Figure 7.11a
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Slide 7.23
The Reflex Arc
 Reflex Arc components:
Usually five (5), may be fewer
 Receptor, sensory neuron, integration
center, motor neuron, effector
Figure 7.11a
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Slide 7.23
The Reflex Arc
 Reflex arc –from receptor to
interneuron, to effector
 Impulse may not go to brain before
reflex occurs
Figure 7.11a
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Slide 7.23
Simple Reflex Arcs
Figure 7.11b, c
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Slide 7.24
Types of Reflexes and Regulation
 Involuntary (Autonomic) reflexes:
Smooth muscle regulation
Heart and blood pressure regulation
Regulation of glands (secretion)
Digestive system regulation
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Slide 7.25
Types of Reflexes and Regulation
 Somatic reflexes
Activation of skeletal muscles
Involuntary movement of a voluntary
muscle
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Slide 7.25
Central Nervous System (CNS)
 CNS develops from the embryonic
neural tube
 Two components:
Brain
Spinal Cord
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Slide 7.26
Regions of the Brain
 Cerebral
hemispheres
 Diencephalon
 Brain stem
 Cerebellum
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 7.12
Slide 7.27
Cerebral Hemispheres (Cerebrum)
 Paired
superior parts
of the brain
 More than
half of brain
mass
Figure 7.13a
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Slide 7.28a
Cerebral Hemispheres (Cerebrum)
 The surface
has ridges
(gyri) and
grooves
(sulci)
Figure 7.13a
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Slide 7.28b
Lobes of the Cerebrum
 Fissures (deep grooves) divide the
cerebral cortex into lobes
 Surface lobes of the cerebral cortex:
 Frontal lobe
 Parietal lobe
 Occipital lobe
 Temporal lobe
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.29a
Lobes of Cerebral Cortex
 Lobes named
for skull
bones lying
superficially
Figure 7.13a
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Slide 7.28b
Lobes of the Cerebrum, median view
Figure 7.15a
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Slide 7.29b
Sensory and Motor Areas of the
Cerebral Cortex
Figure 7.14
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Slide 7.31
Specialized Functions of Lobes
 Frontal Lobes:
Voluntary movement
Concentration
Planning
Problem-solving
Judging consequences of behavior
Broca’s area: speech output
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Slide 7.32a
Specialized Functions of Lobes
 Parietal Lobes:
Sensations from skin: pressure,
temperature, touch,pain
Speech: use, understanding
 Input of language
 Interpretation
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Slide 7.32a
Specialized Functions of Lobes
 Temporal Lobes:
Interpretation of sound
Hearing
Interpretation of smell
 Direct input from olfactory nerves
 Limbic system
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Slide 7.32a
Specialized Functions of Lobes
 Occipital Lobes:
Vision
Combining vision with other senses
Recognition of objects, individuals
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Slide 7.32a
Specialized Functions of Lobes
 Insula:
“fifth lobe”
Hidden in lateral fissure
 Monitors internal organs, i.e., heart
 Responsible for “aversions”
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Slide 7.32a
Specialized Area of the Cerebrum
Figure 7.13c
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Slide 7.32c
Layers of the Cerebrum
 Gray matter
 Outer layer
 Composed of
neuron cell
bodies
Figure 7.13a
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Slide 7.33a
Layers of the Cerebrum
 White matter
 Fiber tracts
deep to gray
matter
 myelinated
 Example:
corpus callosum
Figure 7.13a
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Slide 7.33b
Layers of the Cerebrum
 Basal nuclei – internal islands of
gray matter
 Buried in white matter of
hemispheres
 Assist with posture, balance,
location of sound
Figure 7.13a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.33c
Diencephalon
 Sits above brain stem
 Enclosed by the cerebral hemispheres
 Made of three parts
 Thalamus
 Hypothalamus
 Epithalamus (with pineal body)
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Slide 7.34a
Regions of the Brain
 Diencephalon
 “di” = through or
throughout
Figure 7.12
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Slide 7.27
Diencephalon
Figure 7.15
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Slide 7.34b
Thalamus
 Surrounds the third ventricle
 The relay station for sensory impulses
Exception: sense of smell
 Transfers impulses to the the cortex for
interpretation
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.35
Regions of the Brain
 Thalamus
Figure 7.12
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Slide 7.27
Hypothalamus
 Under the thalamus
 Important autonomic nervous system
center
 Helps regulate body temperature
 Controls water balance
 Regulates metabolism
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Slide 7.36a
Regions of the Brain
 Hypothalamus
Figure 7.12
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Slide 7.27
Hypothalamus
 An important part of the limbic system
(emotions)
 The pituitary gland is attached to the
hypothalamus
 Hypothalamus produces hormone releasing
factors
 Control anterior pituitary gland
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Slide 7.36b
Epithalamus
 Forms the roof of the third ventricle
 Houses the pineal body (an endocrine
gland)
 Includes the choroid plexus – forms
cerebrospinal fluid
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Slide 7.37
Brain Stem
 Attaches brain to the spinal cord
 Parts of the brain stem
 Midbrain
 Pons
 Medulla oblongata
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Slide 7.38a
Brain Stem
Figure 7.15a
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Slide 7.38b
Midbrain
 Mostly composed of tracts of nerve
fibers (myelinated)
 Has four rounded protrusions:
corpora quadrigemina
 Reflex centers for vision and hearing
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.39
Pons
 Pons means “bridge”
 The bulging center part of the brain
stem
 Mostly composed of fiber tracts
 Includes nuclei involved in the control of
breathing
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.40
Medulla Oblongata
 The most inferior part of the brain stem
 Attaches to the spinal cord
 Houses control centers
 Heart rate control
 Blood pressure regulation
 Breathing
 Swallowing
 Vomiting
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.41
Regions of the Brainstem
 Midbrain
 Pons
 Medulla
oblongata
Figure 7.12
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.27