nervous system: part iv 1 the brain · 3 essential knowledge 3.d.2 neurotransmitters act as...
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1 Nervous System: Part IV
The Central Nervous SystemThe Brain
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Can you survive when part of your brain is destroyed?
Now that you have their attention, explain this drawing to students. Phineas P. Gage (1823–1860) was an American railroad construction foreman now remembered for his improbable survival of an accident in which a large iron rod was driven completely through his head, destroying much of his brain's left frontal lobe, and for that injury's reported effects on his personality and behavior, effects so profound—for a time, at least—that friends saw him as "no longer Gage"
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2. Cells communicate with each other through direct contact with other cells or from a distance via
chemical signaling.
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Essential Knowledge 3.D.2
Neurotransmitters act as chemical signals
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Review the primary functions of the nervous system pointing out that today we will be focusing on the structures associated with the processing of the input.
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Central nervoussystem (CNS)
Brain
Spinal cord
Peripheral nervoussystem (PNS)
Cranial nerves
Ganglia outsideCNS
Spinal nerves
The vertebrate nervous system.
Nervous System Part IV: Central Nervous System & Brain TEACHER NOTES needs coding
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Gray matter
Whitematter
Ventricles
What accounts for the difference between white and gray matter?
Point out the ventricles, gray matter, and white matter. Emphasize that the gray matter is made of unmyelinated neurons while the white matter contains myelinated neurons. More than students need to know, but just in case you are asked…White matter, long thought to be passive tissue, actively affects how the brain learns and dysfunctions. Whilst grey matter is primarily associated with processing and cognition, white matter modulates the distribution of action potentials, acting as a relay and coordinating communication between different brain regions. http://en.wikipedia.org/wiki/White_matter
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• The central canal of the spinal cord and the ventricleof the brain are hollow and filled with cerebrospinal fluid
• The cerebrospinal fluid is filtered from blood and functions to cushion the brain and spinal cord as wel as to provide nutrients and remove wastes
Cerebrospinal Fluid
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Glia• Glia have numerous functions
including to nourish, support, and regulate neurons
– Embryonic radial glia form tracks along which newly formed neurons migrate
– Astrocytes induce cells lining capillaries in the CNS to form tight junctions, resulting in a blood-brain barrier and restricting the entry of most substances into the brain
No need for students to “memorize” the diagram, it is included solely for illustration.
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Efferent neuronsAfferent neurons
Central NervousSystem
(information processing)
Peripheral NervousSystem
Sensoryreceptors
Internaland external
stimuli
Autonomicnervous system
Motorsystem
Control ofskeletal muscle
Sympatheticdivision
Parasympatheticdivision
Entericdivision
Control of smooth muscles,cardiac muscles, glands
Use this graphic to describe the relationship between the peripheral and central nervous systems. It outlines the functional hierarchy of the vertebrate peripheral nervous system. Connect this flow chart to the image on the next slide so students will realize the information isn’t something different but is an extension of the same.
Nervous System Part IV: Central Nervous System & Brain TEACHER NOTES needs coding
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The peripheral system involves more than just muscles and eyes. It includes all of the sensory structures and the responding structures (glands, muscles, etc.)
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Efferent neuronsAfferent neurons
Central NervousSystem
(information processing)
Peripheral NervousSystem
Sensoryreceptors
Internaland external
stimuli
Autonomicnervous system
Motorsystem
Control ofskeletal muscle
Sympatheticdivision
Parasympatheticdivision
Entericdivision
Control of smooth muscles,cardiac muscles, glands
Revisit this graphic and think about using a specific example, let’s say you smell good food cooking and it makes your mouth water. What is your sensory receptor? (smell receptors) Where does the impulse travel to next? (along a sensory/afferent neuron to the brain) Once the information is processed by your brain where does information travel? (along motor/efferent neuron to salivary gland)
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The Vertebrate Brain Is Regionally Specialized
• Specific brain structures are particularly specialized for diverse functions
• These structures arise during embryonic development
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Human Embryonic Brain Developme
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Scroll over the bottom of the picture to activate the animation’s controls and press play. This movie is from a series of lectures given at the Howard Hughes Medical Institute (HHMI) in 2008. http://www.hhmi.org/biointeractive/neuroscience/dev_human_emb_brain.html The next goes into a bit more detail about human embryonic brain development.
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Embryonic brain regions Brain structures in child and adult
Forebrain
Midbrain
Hindbrain
Telencephalon
Diencephalon
Mesencephalon
Metencephalon
Myelencephalon
Cerebrum (includes cerebral cortex, whitematter, basal nuclei)
Diencephalon (thalamus, hypothalamus,epithalamus)
Midbrain (part of brainstem)
Pons (part of brainstem), cerebellum
Medulla oblongata (part of brainstem)
Midbrain
Forebrain
Hindbrain
Telencephalon
Diencephalon
MesencephalonMetencephalon
Myelencephalon
Spinal cord
Cerebrum Diencephalo
Midbra
PonsMedullaoblonga
CerebellumSpinal cor
ChildEmbryo at 5 weeksEmbryo at 1 month
Exploring: The Organization of the Human Brain Spend a few minutes explaining this . Additional pertinent details follow on the next few slides.
Nervous System Part IV: Central Nervous System & Brain TEACHER NOTES needs coding
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Brain structures in child and adult
Forebrain
Midbrain
HindbrainMyelencephalon
Cerebrum (includes cerebral cortex, whitematter, basal nuclei)
Diencephalon (thalamus, hypothalamus,epithalamus)
Midbrain (part of brainstem)
Pons (part of brainstem), cerebellum
Medulla oblongata (part of brainstem)
Midbrain
Forebrain
Hindbrain
Telencephalon
Diencephalon
MesencephalonMetencephalon
Myelencephalon
Spinal cord
Cerebrum Diencephalo
Midbra
PonsMedullaoblonga
CerebellumSpinal cor
ChildEmbryo at 5 weeksEmbryo at 1 month
Exploring: The Organization of the Human Brain Spend a few minutes explaining this slide. Additional pertinent details follow on the next few slides.
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Cerebrum Diencephalon
Midbrain
Pons
Medullaoblongata
CerebellumSpinal cord
Child
An enlargement of a child’s brain.
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Adult brain viewed from the rear
Cerebellum
Basal nucleiCerebrum
Left cerebralhemisphere
Right cerebralhemisphere
Cerebral cortex
Corpus callosum
Exploring: The Organization of the Human Brain
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Diencephalon
ThalamusPineal glandHypothalamusPituitary gland
Spinal cord
Brainstem
Midbrain
Pons
Medullaoblongata
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Motor cortex(control ofskeletal muscles)
Frontal lobe
Prefrontal cortex(decision making,planning)
Broca’s area(forming speech)
Temporal lobe
Auditory cortex (hearing)
Wernicke’s area(comprehending language)
Somatosensory cortex(sense of touch)
Parietal lobe
Sensory associationcortex (integration ofsensory information)
Visual associationcortex (combiningimages and objectrecognition)
Occipital lobe
CerebellumVisual cortex(processing visualstimuli and patternrecognition)
Nervous System Part IV: Central Nervous System & Brain TEACHER NOTES needs coding
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Language and Speech
• Studies of brain activity have mapped areas responsible for language and speech
• Broca’s area in the frontal lobe is active when speech is generated
• Wernicke’s area in the temporal lobe is active when speech is heard
• These areas belong to a larger network of regions involved in language
Just interesting: The first language area within the left hemisphere to be discovered is Broca's area, named after Paul Broca, who discovered the area while studying patients with a language disorder. Broca's area doesn't just handle getting language out in a motor sense, though. It seems to be more generally involved in the ability to process grammar itself, at least the more complex aspects of grammar. For example, it handles distinguishing a sentence in passive form from a simpler subject-verb-object sentence — the difference between "The girl was hit by the boy" and "The boy hit the girl.“ The second language area to be discovered is called Wernicke's area, after Carl Wernicke, a German neurologist who discovered the area while studying patients who had similar symptoms to Broca's area patients but damage to a different part of their brain. These people had damage to an area of the brain that affected speech comprehension called receptive aphasia. People with receptive aphasia also have difficulty recalling the names of objects, often responding with words that sound similar, or the names of related things, as if they are having a hard time recalling word associations.
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Information Processing• The cerebral cortex receives input from sensory
organs and somatosensory receptors• Somatosensory receptors provide information about
touch, pain, pressure, temperature, and the position of muscles and limbs
• The thalamus directs different types of input to distinct locations
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Frontal lobe Parietal lobe
Primarymotor cortex
Primarysomatosensorycortex
GenitaliaToes
Abdominalorgans
Tongue
Jaw
HipKnee
TonguePharynx
Head
Neck
TrunkHip
Body part representation in the primary motor and primary somatosensory cortices.
Nervous System Part IV: Central Nervous System & Brain TEACHER NOTES needs coding
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Primarymotor cortex
Toes
Tongue
Jaw
HipKnee
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Primarysomatosensorycortex
Genitalia
Abdominalorgans
TonguePharynx
Head
Neck
TrunkHipLeg
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Frontal Lobe Function
• Frontal lobe damage may impair decision making and emotional responses but leave intellect and memory intact
• The frontal lobes have a substantial effect on “executive functions” of thinking making decisions.
26 Created by:
Debra RichardsCoordinator of Secondary Science ProgramsBryan ISDBryan, TX
Nervous System Part IV: Central Nervous System & Brain TEACHER NOTES needs coding
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