AN SC 310 - 8
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AN SC 310 - 8
AN SC 310
Lecture 8 - The Nervous System: CNS
What percentage of the CNS is composed of glia?
What are the 5 types of glial cells?
Ependymal cells (line cavities)
Schwann cells (myelin)
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
What are the functions of Microglia?
Protect CNS from foreign matter through phagocytosis
Protect CNS from oxidative stress
What are the 3 physical support groups and their subgroups of the CNS?
Bone - cranium, vertebrae
Meninges - dura mater, arachnoid mater, pia mater
What are the properties of CSF?
Clear watery fluid bathing the CNS
Secreted by ependymal cells of the choroid plexus
Maintains stable ISF
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
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
What is the blood-brain barrier?
Special anatomy of CNS capillaries which limit exchange btwn blood & ISF
What are the structures associated with gray and white matter?
Gray = cell bodies, dendrites, axon terminals
White = axons
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
What are the properties of the spinal cord?
Cylindrical nervous tissue
Surrounded by vertebral column
Spinal nerves branch off
What are the 5 different types of spinal nerves from neck down?
Cervical - 8
Thoracic - 12
Lumbar - 5
Sacral - 5
Coccygeal - 1
What is the funciton of gray matter in the spine?
Dorsal - sensory functions
Ventral - motor functions
What does the white matter form in the spine?
Ascending and descending tracts
What are the subdivisions of the brain?
Forebrain - cerebrum (cerebral cortex, basal nuclei). diencephalon (thalamus, hypothalamus)
Brainstem - midbrain, pons, medulla
What are the properties of the cerebellum?
Cortex and nuclei
Motor coordination and balance
Eye and body movements
What is the function of the brainstem?
Connects forebrain and cerebellum to spinal cord
Processing center for 10 of the 12 cranial nerves
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)
What are the physical characteristics of the cerebral cortex?
Gyri - ridges
Sulci - grooves
Lobes - frontal, parietal, occipital, temporal
Where is the primary motor cortex located?
Where is the somatosensory cortex located?
What does brain lateralization mean?
Sensory and motor pathways cross
R brain perceives/controls L input/muscles
L brain perceives/controls R input/muscles
What do the R and L brain specialize in?
R - creativity, spatial perception
L - logic, analytical abilities, language
What are the 4 basal nuclei structures?
What are the functions of the basal nuclei?
Inhibit unwanted movements
Select purposeful movements
What is the function of the thalamus?
Integrate sensory and motor info
Sensory relay to cortex
What is the function of the hypothalamus?
Link btwn nervouse and endocrine system
What are the structures of the Limbic System?
Portions of thalamus
Portions of hypothalamus
What are the function of the limbic system?