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At the center of everything… but separated by layers of membranes. Central Nervous System. It’s all about connections…. Brain spinal cord via foramen magnum Spinal cord runs through vertebral canal, formed by vertebral foramina. Meninges mater (umm… matter ). - PowerPoint PPT Presentation
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CENTRAL NERVOUS SYSTEM
At the center of everything… but separated by layers of membranes
It’s all about connections… Brain spinal cord via foramen
magnum Spinal cord runs through vertebral canal,
formed by vertebral foramina
Meninges mater (umm… matter) Dura mater – “durable” tough, dense;
protection from impact, friction Arachnoid mater – cushion from impact
Subarachnoid space – CSF runs here Pia mater – in the “pits”
direct contactCarries blood vessels Forms nerve sheathsHelps form CSF
More on the pia mater Associated with choroid plexus
Secretes CSFCombination of blood vessels & neuroglia
○ Remember which kind? Ependymal cells
It’s not all black and white… but it is gray! Gray matter = unmyelinated neuron cell
bodiesAccumulate lipofuscinFound primarily in cortex (surface of brain)
○ Highly folded/ridged = gyriIncrease surface area
Small pockets of gray found in interior White matter = myelinated axons, neuroglia
Found in brain’s interior In spinal cord, colors are reversed… outside
white, inside gray
Concept check! 1. Describe the three layers of the
meninges 2. What is the function of the choroid
plexus? 3. Describe the locations of gray and
white matter in the CNSWhy are they those colors?
The Brain
Three-Pound Marvel: The Brain Billions of neurons, neuroglia
Most multipolar (1 axon, many dendrites)Receive many signals, process them
Tracts of axonsInformation conduit other regions of brain,
body
Forebrain: Cerebrum and diencephalon Largest, most anterior portion
EmotionsMemoryMotor movementThought
Contain basal nuclei, cerebral cortex
Forebrain: Basal nuclei/ganglia 4 pockets of gray matter – relay motor
information to spinal cordPermit coordinated, steady body
movements
Cerebral cortex Convoluted gray matter covering brain Large surface area (18 sq ft.)
Blood-brain barrier Cerebral cortex nourished by vessels in
arachnoid layer “Barrier” exists between bloodstream
and CSF… Which neuroglia create this?Astrocytes!
Prevents harmful substances from entering brain (also medications)
Cerebral Hemispheres Halves of cerebrum divided by
longitudinal cerebral fissure Some division of labor…
But you use both halves!
Communication between hemispheres Corpus callosum connects left and
right hemispheresContributes to plasticity of brain
Four lobes of the cerebrum
Central sulcus
Lateral sulcus
Brain stem?
Areas of specialization
Deep, medial portion Hypothalamus, thalamus, ventricles
Thalamus Sensation, spatial
sense, motor signals to cortex
Surrounds 3rd ventricle
Hypothalamus Link nervous
system to endocrine system via pituitary gland
Ventricles 4 connected cavities in the forebrain that
contain CSF Associated w/ choroid plexus, continue
into spinal cord Protect brain from trauma
Internal cushion Swelling: hydrocephaly
Brainstem: Midbrain & Hindbrain
Midbrain Strip of neurons, connects cerebrum to hindbrain.
Smallest region of the brain
Relay station for audio and visual info
Eye movement Substantia nigra:
dopamine neurons
Hindbrain
Pons Attached to midbrain Organize & transmit sensory info from
the body
Medulla oblongata Reg’s involuntary body functions
BPBreathingHeart rateSwallowing
Cerebellum Posterior to pons Means “little cerebrum”
In appearance only Balance Posture Coordination of body movement
The Spinal Cord
Spinal Cord Where does it
start from? (picture)
Paper towel roll Blanket Model of spine
White matter15 pairs nerve tractsAscending tracts
○ Dorsal○ Sensory to the brain
Descending tracts○ Lateral & ventral○ Motor info to
effectorsExtrapyramidal tracts
○ Info from medulla oblongata posture & muscle tone
Gray matter Made of nerve cell
bodies reflexes Transfer info to white
matter Dorsal horn
sensory Ventral horn
MotorWhite mattermuscles
Intermediate gray matterb/t “wings”Sensory/motor for
glands/muscles
Spinal nerves 31 pairs spinal nerves Part of PNS Reflex arcs for respective body regions