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Ex 19
Brain and Cranial Nerves
Meninges RevisitedDura Mater
tough outermost coveringcreates sinuses and ligaments
Arachnoidclosely associated with the durasubarachnoid space contains the CSF and cerebral vasculaturearachnoid villi, transfers CSF from subarachnoid space to venous vasculature
Pia Materdelicate tissue over brainattached by astrocytesblood vessels lie on top of it
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Meninges RevisitedDura Mater differences
two layersouter fibrous
fused to periosteuminner fibrous
two layers can separate to create spaces called venous sinuses
collect most of the blood from the braindrain into the internal jugular vein
Meninges RevisitedDural Ligaments
folds of inner dural layer that act to support the brain
Falx Cerebribetween hemispheressuperior & inferior sagittal sinus
Tentorium Cerebellibetween cerebrum and cerebellumtransverse sinus
Falx Cerebellibetween cerebellar hemispheres
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VentriclesSpaces within the brain filled with CSF
2 lateral ventricles3rd ventricle4th ventricle
CSF is created in the ventricles in structures called choroid plexilateral ventricles connected through the interventricular foraminathe third and fourth ventricles are connected through the cerebral aqueductCSF gets into the subarachnoid space through the median and lateral aperturesremember that CSF gets back into the blood through the arachnoid villi
Ventricles
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Area of brain devoted to higher level functions
gray matter (outside)neural cell bodies, dendrites, unmyelinated axons, support cells
white matter (inside)tracts of information
corpus callosuminternal capsule
nucleiislands of grey matter
Cerebrum
Divided into right and left hemispheresHemispheres divided into lobes:
Frontal LobeParietal LobeTemporal LobeOccipital Lobe
Cerebrum
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CerebrumFissures: deep grooves in the cerebrum
longitudinal fissurebetween hemispheres
transverse fissurebetween cerebrum and cerebellum
CerebrumSulci: shallow depressions in gray matter
Central Sulcusdivides frontal and parietal lobes
Lateral Sulcusdivides the temporal from the parietal lobes
Gyri: ridges in gray matter to increase surface area
precentral gyrusprimary motor cortex
postcentral gyrussomatosensory area
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Functions of the lobesFrontal Lobe
motor, speech (l. lobe), personality
Parietal Lobesensation (except smell, language
Temporal Lobehearing, smell, language
Occipital Lobevision
Cerebrum
Diencephalon
ThalamausHypothalamusEpithalamus
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DiencephalonThalamus
bulges into the 3rd ventriclepaired, oval areas of grey matter and white matter tractsacts as a relay station for sensory input
DiencephalonHypothalamus
nucleimajor regulation
mamillary bodiesprocess olfactory sensations
pituitaryhormonal regulationattached via the infundibulum
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Diencephalon
Functions of Hypothalamuscontrols somatic motor activities at the subconscious levelcontrols autonomic functioncoordinates activities of the nervous and endocrine systemssecretes hormonesproduces emotional and behavioral drivecoordinates voluntary and autonomic functionsregulates body temperaturecoordinates circadian cycles of activity
DiencephalonEpithalamus
pineal gland
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Basal GangliaBasal Ganglia
control motor movements that don’t require much thought: arm swinging, muscle tone, smiling.sets muscle tone
defects in dopamine regulation in these structures results in Parkinson’s disease
Diencephalon & Basal GangliaCorpus Callosum
area where axons cross over
Caudate Nucleus
Putamen
Globus Pallidus
Thalamus
tail of caudate nucleus
corpus callosum
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Cerebellumfine tunes and coordinates motor movements
people with cerebellar deficiencies have problems with balance and position
Cerebellar Hemispheres
Vermix
CerebellumArbor Vitae
tracts of white matter in the cerebellum
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Brain Stem
Mesencephalon (midbrain)
Pons
Medulla Oblongata
MidbrainLies inferior to thalamusCorpora Quadrigemina
superior colliculireflexes for vision such as tracking and pupillary reflexes
inferior colliculiauditory pathways to the thalamusresponsible for startle reflex
CV III and IV arise from midbrainMidbrain also acts as motor relay and does some processing of motor informationCerebral peduncles
motor pathways on anterior side of midbrain
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MidbrainLies inferior to thalamusCorpora Quadrigemina
superior colliculireflexes for vision such as tracking and pupillary reflexes
inferior colliculiauditory pathways to the thalamusresponsible for startle reflex
CV III and IV arise from midbrainMidbrain also acts as motor relay and does some processing of motor informationCerebral peduncles
motor pathways on anterior side of midbrain
PonsPons
“bridge”one of the first relay areas for motor informationcontains apneustic and pneumotaxic areas
modify activity of medullar respiritory areas
CN V, VI, VII and VIII
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MedullaMedulla
pyramidsdecussation of pyramids
olivary nucleicardiovascular center, rhythmicity area, embarrassing bodily functions area: vomiting, coughing, sneezingCN VIII-XII
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