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What percentage of the CNS is composed of glia?
90%
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What are the 5 types of glial cells?
- Astrocyte
- Ependymal cells (line cavities)
- Microglia (phagocytes)
- Oligodendrocytes (myelin)
- Schwann cells (myelin)
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What are the functions of Astrocytes?
- Develop neural connections
- Modulate synaptic activity
- Remove NT from synaptic cleft
- Communicate to neurons through chemical messengers
- Maintain normal electrolyte composition of ISF in CNS
- Protect neurons against toxic substances/oxidative stress
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What are the functions of Microglia?
- Protect CNS from foreign matter through phagocytosis
- Protect CNS from oxidative stress
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What are the 3 physical support groups and their subgroups of the CNS?
Bone - cranium, vertebrae
Meninges - dura mater, arachnoid mater, pia mater
CSF
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What are the properties of CSF?
- Clear watery fluid bathing the CNS
- Secreted by ependymal cells of the choroid plexus
- Cushions brain
- Maintains stable ISF
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What are the properties of CSF production?
Total volume of CSF = 125-150 mL
Choroid plexus produces 400 -500 mL/day
Recycled 3 times/day
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What is significant about the blood supply to the CNS?
CNS = 2% of body weight, receives 15% of blood supply
- Brain uses 20% of oxygen, 50% of glucose
- No glycogen stores
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What is the blood-brain barrier?
Special anatomy of CNS capillaries which limit exchange btwn blood & ISF
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What are the structures associated with gray and white matter?
- Gray = cell bodies, dendrites, axon terminals
- White = axons
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What are the functions of the white matter in the brain?
Projection fibers - cerebral cortex with lower levels of brain or spinal cord
Association fibres - connect 2 areas of cerebral cortex on same side of brain
Commissural fibres - connect same corical regions on 2 sides of brain
Corpus collosum - primary location of commissural fibres
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What are the properties of the spinal cord?
- Cylindrical nervous tissue
- Surrounded by vertebral column
- Spinal nerves branch off
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What are the 5 different types of spinal nerves from neck down?
- Cervical - 8
- Thoracic - 12
- Lumbar - 5
- Sacral - 5
- Coccygeal - 1
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What is the funciton of gray matter in the spine?
- Functional Halves
- Dorsal - sensory functions
- Ventral - motor functions
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What does the white matter form in the spine?
Ascending and descending tracts
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What are the subdivisions of the brain?
- Forebrain - cerebrum (cerebral cortex, basal nuclei). diencephalon (thalamus, hypothalamus)
- Cerebellum
- Brainstem - midbrain, pons, medulla
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What are the properties of the cerebellum?
- Bilaterally symmetrical
- Cortex and nuclei
- Motor coordination and balance
- Eye and body movements
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What is the function of the brainstem?
- Connects forebrain and cerebellum to spinal cord
- Processing center for 10 of the 12 cranial nerves
- Reticular formation
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What are the properties of the Cerebral Cortex?
- Outermost portion of cerebrum
- Thin convoluted layer of gray matter
- Highest level of neural processing (perception of environment, ides, recall, command body movement)
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What are the physical characteristics of the cerebral cortex?
- Gyri - ridges
- Sulci - grooves
- Layers
- Lobes - frontal, parietal, occipital, temporal
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Where is the primary motor cortex located?
Frontal lobe
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Where is the somatosensory cortex located?
Parietal cortex
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What does brain lateralization mean?
- Sensory and motor pathways cross
- R brain perceives/controls L input/muscles
- L brain perceives/controls R input/muscles
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What do the R and L brain specialize in?
- R - creativity, spatial perception
- L - logic, analytical abilities, language
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What are the 4 basal nuclei structures?
- Globus pallidus
- Caudate
- Putamen
- Claustrum
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What are the functions of the basal nuclei?
- Inhibit unwanted movements
- Select purposeful movements
- Postural support
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What is the function of the thalamus?
- Integrate sensory and motor info
- Sensory relay to cortex
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What is the function of the hypothalamus?
- Food intake
- Thermoregulation
- Link btwn nervouse and endocrine system
- Circadian rhythms
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What are the structures of the Limbic System?
- Amygdala
- Hippocampus
- Fornix
- Cingulate gyrus
- Portions of thalamus
- Portions of hypothalamus
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What are the function of the limbic system?
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