Transcript Nerve activates contraction

Chapter 7
The Nervous System
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Organization of the
Nervous System
 Central Nervous System
 Referred to CNS
 Brain and Spinal cord
 Integrative control center
 Peripheral Nervous System
 Referred to PNS
 Nerves that extend outside the brain and spinal
cord to the body’s extremities
 Communicates between the CNS and the rest of
the body
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Regions of the Brain
 Cerebrum
 Diencephalon
 Cerebellum
 Midbrain *
 Pons *
 Medulla Oblongata *
* Found in Brain Stem
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Cerebral Hemispheres (Cerebrum)
 Largest part of brain
 Include more than half of the brain mass
 Controls higher mental functions;
conscious mind; MAKES US HUMAN
 Allows us to sense, to communicate, to
remember, and to understand, and
initiate voluntary movements.
 Outer layer of cerebrum (cerebral cortex) is made of gray matter
- Folded surface increases surface area
- Elevated ridges (gyri)
- Shallow depressions (sulci)
- Deep Grooves (fissures)
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Cortex Roadmap
 Gyri - ridges
 Sulci – shallow grooves
 Fissures – deep groves
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Lobes of the Cerebrum
 Surface lobes of the cerebrum
 Frontal lobe
 Parietal lobe
 Occipital lobe
 Temporal lobe
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Sensory and Motor
Areas of the
Cerebral Cortex
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Specialized Areas of the Cerebrum
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Layers of the Cerebrum
 Gray matter
 Outer layer
 Composed mostly of neuron
cell bodies
 Includes regions of the brain
involved in muscle control,
sensory perceptions, like seeing
and hearing, memory, emotions
and speech
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Layers of the Cerebrum
 White matter
 Contains mainly long,
myelinated axons
 Involved in the relay of
sensory information from
the rest of the body to the
cerebral cortex
Figure 7.13a
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Diencephalon
 Sits on top of the brain
stem
 Enclosed by the
cerebral hemispheres;
well-hidden brain
region
 Made of three parts
 Thalamus
 Hypothalamus
 Epithalamus
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Thalamus
 The relay station for
sensory impulses
(switchboard)
 Transfers impulses to the
correct part of the
cerebrum for interpretation
 All incoming impulses get
sorted here first and
identified as pleasant or
non-pleasant
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Hypothalamus
 Under the thalamus
 Contains brain stem and controls organs by maintaining
homeostasis
 Important autonomic nervous system center
 Helps regulate body temperature
 Controls water balance
 Regulates metabolism
 An important part of the limbic system (emotions)
 The pituitary gland is attached to the hypothalamus
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Hypothalamus
 An important part of the limbic system
(emotions)
 The pituitary gland is attached to the
hypothalamus which secretes hormones to
maintain homeostasis
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Epithalamus
 Makes the cerebrospinal
fluid
 Helps to regulate the
sleep/wake cycle by
releasing hormones like
melatonin
 Controls some parts of
emotions and mood
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Epithalamus
Brain Stem
 Attaches to the spinal
cord; primitive “rat
brain”
 Controls automatic
behaviors necessary for
survival (breathing)
 Parts of the brain stem
each about an inch long
 Midbrain
 Pons
 Medulla oblongata
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Midbrain
 Smallest region of the brain that sort of works as a
relay station for auditory and visual information.
 Also controls eye movements, like blinking
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Pons
 The bulging center part of the brain stem
 Mostly composed of fiber tracts which relay messages
to the brain
 Includes control of breathing
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Medulla Oblongata
 The lowest part of the brain stem
 Merges into the spinal cord
 Includes important fiber tracts relaying messages
 Contains important control centers
 Heart rate control
 Blood pressure regulation
 Breathing
 Swallowing
 Vomiting
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Cerebellum
 contains ~70% of all the brain's neurons; yet is
only 10% of the volume of the brain!
 contributes to precise timing of skeletal muscle
activity (i.e. walking, running or standing on
your hands)
 controls our balance and equilibrium
 Doesn’t function well under influence of alcohol
 Works like ‘auto pilot’ – monitors body position
and amount of tension in body parts
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Cerebellum and other brain parts
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings