CHAPTER 12 CENTRAL NERVOUS SYSTEM – BRAIN
Central Nervous system
•braincontrol center
•spinal cordsuperhighway
Brain – developmental areas
•telencephaloncerebrum
•diencephalonthalamus
hypothalamus
epithalamus
•mesencephalonmidbrain
•metencephalonpons cerebellum
•myelencephalonmedulla oblongata
•brain stem =midbrain pons medulla oblongata
Cerebrum
•R and L cerebral hemispheres
•gray mattercell bodies and interneurons
•outer gray matter=cortex
•inner gray matter
•white mattermyelinated axons
bumps and grooves
•gyrusbumps
•sulcusgrooves
•fissuredeep sulcus
•longitudinal fissureseparate hemispheres
•transverse cerebral fissureseparates cerebrum from cerebellum
•lateral sulcusbetw
•parieto-occipital sulcus
•central sulcus
•precentral gyrus
•postcentral gyrus
CNS – dorsal / ventral
•dorsalsensory
•ventralmotor
Lobes of Cerebrum
•frontal lobe
•parietal lobe
•temporal lobe
•occipital lobe
•insulainternal at lateral sulcus
cortex functional areas
•motor
–conscious motorfrontal - precentral gyrus
–eye movementfrontal
–speech movementfrontal (Broca’s area)
•sensory
–conscious sensationparietal – postcentral gyrus
–auditorytemporal
–olfactorytemporal , limbic system
–visualoccipital
–taste parietal
–equilibriuminsula ?
frontal lobe
•primary motor cortexconscious motor
–precentral gyrus
–pyramidal cells pyramidal (corticospinal) tract
•frontal eye field
•Broca’s area
frontal lobe
•premotor cortexcomplex, learned movements
•prefrontal cortexsocial skills emotion
parietal lobe
•primary somatosensory cortex
–post-central gyrus
•taste (gustatory)
•Wernicke’s areaunderstanding spoken words also in temporal lobe
occipital lobe
•primary visual cortexlargest sensory area (humans)
•visual association areaanalyzing visual information memory of “
temporal lobe
•primary auditory cortex
•Wernicke’s areaunderstanding spoken words
white matter
•commissural fibers
–corpus callosum
•association fibersareas on same hemisphere
•projection fibers
–internal capsule
–corona radiata
internal gray matter
• Basal ganglia
• Thalamus
• Hypothalamus
• epithalamus
basal ganglia = basal nuclei
•lentiform nuclei
–globus pallidus
–putamen
•caudate nucleus
•functions :start and stop movements intensity of movement works with Substantia Nigra
Thalamus
•“gateway to the cerebrum”
•sensory relay
–all sensory info to cortex goes through thalamus
•sensory filter weak, unimportant stimuli
Hypothalamus
•visceral control centerregulates organ functions
–temperature
–hunger glucose, amino acids
–thirstsalts, water
–Autonomic NS
–emotionsvisceral responses
–endocrine controls Pituitary gland
–sleep-wake cyclesinput from optic nerve
epithalamus
•pineal gland
•secretes melatoninstimulates sleep cycle
•control from hypothalamus
brain stem
•3 parts :
–midbrain
–pons
–medulla oblongata
•vital functions
•passageway betw cortex and spinal cord
•cranial nerves
midbrain
•cranial nerves nucleiIII , IV
•corpora quadrigemina
–superior colliculivisual reflexes
–inferior colliculiauditory reflexes
•cerebral pedunclespyramidal motor tracts
•superior cerebellar peduncles cerebellum to midbrain
•substantia nigrainfluences basal ganglia produces Dopamine
•red nucleusflexion movements
muscle tone
pons
•cranial nerves nucleiV , VI , VII
•middle cerebellar peduncles
–axons from pons to cerebellum
•respiratory centers
medulla oblongata
•cranial nerve nucleiVIII, IX, X, XI, XII
•visceral motor nucleicardiac center HR vasomotor center BP respiratory center resp rate
•inferior cerebellar peduncles medulla to cerebellum
•pyramidspyramidal tracts
medulla oblongata – relay functions
•vestibular nucleiequilibrium relay
•cochlear nucleiauditory relay
•olivary nucleiproprioception relay
•nucleus gracilis ; cuneatustouch, pressure relay
•solitary nucleustaste
•reflexesswallow cough sneeze BP , HR , Resp
cerebellum
•coordination of voluntary movements
•cerebellar hemispheres
•vermisconnects hemispheres
•arbor vitaewhite matter (inner)
•cerebellar pedunclesconnect to brain stem
–superiormidbrainto cerebrum
–middleponsfrom cerebrum
–inferiormedullafrom body
limbic system
•emotional brain
–amygdalafear, anger
–cingulate gyrusemotions, gestures
•memory / learning
–hippocampusshort term memory
–amygdalamemories of emotions
–hypothalamusvisceral responses
•fornixconnects 2 limbus
reticular formation
•center of brain stem
•reticular activating system (RAS)
–maintains consciousness and alertness
•input from all senses
•motor to all muscles
meninges
•cover and protect CNS
•Dura materouter
–periosteal layerlines skull
–meningeal layerprotects ; limits movement
•falx cerebrilongitudinal fissure secured to crista galli
•tentorium cerebelli
–dural sinusesdrains excess CSF
•Arachnoidmiddle
–subarachnoid spacecontains CSF
–arachnoid villiproject into dural sinuses
•Pia materinnercovers CNS surface
cerebrospinal fluid
•liquid cushion
•nourish brain and remove wastes
•choroid plexusproduces CSF from plasma ependymal cells of ventricles
•flows through ventriclessubarachnoid space central canal of spinal cord
•drains into dural sinuses then into veins
ventricles
•brain’s central cavity
•lateral ventriclesin cerebral hemispheres
–septum pellucidummedian membrane
•third ventriclein diencephalon
–cerebral aqueductconnects 3rd and 4th
•fourth ventricledorsal to pons
–aperturesconnect to subarachnoid space
–central canalcontinues in spinal cord