CNS and PNS
Central Nervous System (CNS)
CNS consists of brain and spinal cord
Adult Brain Regions1. Brain stem (midbrain, pons, and medulla)
2. Cerebellum
3. Diencephalon
4. Cerebral hemispheres
Cerebralhemisphere
Diencephalon
Cerebellum
Brain stem• Midbrain• Pons• Medulla oblongata
Brain Stem
Three regions Midbrain Pons Medulla oblongata
Lateral ventricle(covered by septumpellucidum)
Third ventricle
Anterior commissure
Hypothalamus
Corpus callosumFornix
Thalamus
PosteriorcommissurePineal gland
Corporaquadrigemina
Cerebralaqueduct
Midbrain
Arbor vitae
Fourth ventricle
Cerebellum
Medulla oblongata
Pons
Optic chiasma
Epithalamus
Mammillary body
Brain StemControls automatic behaviors necessary for
survival Breathing Circulation Digestion Swallowing
Frontal lobe
Olfactory bulb(synapse point ofcranial nerve I)
Optic nerve (II)
Optic chiasma
Optic tract
Mammillary body
Midbrain
Pons
Temporallobe
Medullaoblongata
Cerebellum
Spinal cord
MidbrainAssociated with vision, hearing,
motor control, sleep/wake, arousal (alertness), and temperature regulation.
Substantia nigra—functionally linked to basal nuclei
TectumPeriaqueductal gray matterOculomotor nucleus (III)
Dorsal
Medial lemniscusRed nucleusSubstantianigraFibers ofpyramidal tract
Superiorcolliculus
Cerebral aqueduct
Reticular formation
Crus cerebri of cerebral peduncle
Ventral
Midbrain
PonsFibers of pons
Connect higher brain centers and spinal cord
Nuclei that relay signals from the forebrain to the cerebellum, along with nuclei that deal primarily with
sleep, respiration, swallowing, bladder control, hearing, equilibrium, taste, eye movement, facial expressions, facial sensation, and posture.
Superior cerebellar peduncleTrigeminalmain sensorynucleusTrigeminal motor nucleusMiddle cerebellarpeduncleTrigeminalnerve (V)Medial lemniscus
Fourthventricle
Reticularformation
Pontine nuclei
Fibers of pyramidaltractPons
Medulla Oblongata: FunctionsCardiovascular center
Cardiac center adjusts force and rate of heart contraction
Respiratory centers Generate respiratory rhythm Control rate and depth of breathing (with pontine
centers)
Medulla OblongataAdditional centers regulate
Vomiting Hiccuping Swallowing Coughing Sneezing
Cerebellum Input from cortex, brain stem and sensory
receptors
Allows smooth, coordinated movements Learn to ride a bicycle
Anterior lobeArbor vitae
Cerebellar cortex
Pons
Fourth ventricle
Medulla oblongata
Posterior lobe
Flocculonodular lobeChoroid plexus
AnteriorlobePrimaryfissure
Posteriorlobe
Horizontalfissure
Vermis Vermis
Cerebellar Processing of Motor ActivityCerebellum receives impulses
from cerebral cortex of intent to initiate voluntary muscle contraction
Continuously "inform" cerebellum of body's position and momentumProprioception
Smoothly coordinate muscle contraction
Basal Nuclei (Ganglia)Caudate nucleus
Putamen
Globus pallidus
CaudatenucleusPutamen
Striatum Thalamus
Tail of caudatenucleus
Cerebral cortex
Cerebral white matter
Corpus callosum
Anterior hornof lateral ventricle
PutamenGlobus pallidus
Thalamus
Third ventricle
Inferior hornof lateral ventricle
Head of caudate nucleus
Tail of caudate nucleus
Anterior
Posterior
Functions of Basal NucleiFunctions thought to be
Helps in balance
Diencephalon Thalamus Hypothalamus Epithalamus
Cerebral hemisphere
Septum pellucidum
Interthalamicadhesion(intermediatemass of thalamus)
InterventricularforamenAnteriorcommissureHypothalamusOptic chiasma
Pituitary glandMammillary bodyPonsMedulla oblongataSpinal cord
Corpus callosum
Fornix
Choroid plexus
Thalamus(encloses third ventricle)
PosteriorcommissurePineal gland
Epithalamus
CorporaquadrigeminaCerebralaqueduct
Midbrain
Arbor vitae (of cerebellum)Fourth ventricleChoroid plexusCerebellum
Thalamic Function“Router” to cerebral cortex
Sorts, edits, and relays ascending input
HypothalamusUnderneath the Thalamus
Contains many nuclei
AnteriorcommissurePreopticnucleusAnteriorhypothalamicnucleusSupraopticnucleusSuprachiasmaticnucleus
OpticchiasmaInfundibulum(stalk of thepituitary gland)
Paraventricularnucleus
FornixDorsomedialnucleus
PosteriorhypothalamicnucleusLateralhypothalamicarea
VentromedialnucleusMammillarybody
ArcuatenucleusPituitarygland
The main hypothalamic nuclei.
Hypothalamic FunctionControls autonomic nervous system (e.g.,
blood pressure, rate and force of heartbeat, digestive tract motility, pupil size)
Physical responses to emotions (limbic system) Perception of pleasure, fear, and rage, and in
biological rhythms and drives
Hypothalamic FunctionRegulates sleep-wake cycles
Controls endocrine system Controls secretions of anterior pituitary gland Produces posterior pituitary hormones
Hypothalamic FunctionRegulates body temperature –
sweating/shivering
Regulates hunger and satiety in response to nutrient blood levels or hormones
Regulates water balance and thirst
Cerebral hemisphere
Septum pellucidum
Interthalamicadhesion(intermediatemass of thalamus)
InterventricularforamenAnteriorcommissureHypothalamusOptic chiasma
Pituitary glandMammillary bodyPonsMedulla oblongataSpinal cord
Corpus callosum
Fornix
Choroid plexus
Thalamus(encloses third ventricle)
PosteriorcommissurePineal gland
Epithalamus
CorporaquadrigeminaCerebralaqueduct
Midbrain
Arbor vitae (of cerebellum)Fourth ventricleChoroid plexusCerebellum
EpithalamusConnect the limbic system to other parts of the
brain Regulation of emotions
Pineal gland secretes melatonin Involved in circadian rhythms
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Lateral ventricle(covered by septumpellucidum)
Third ventricle
Anterior commissure
Hypothalamus
Corpus callosumFornix
Thalamus
PosteriorcommissurePineal gland
Corporaquadrigemina
Cerebralaqueduct
Midbrain
Arbor vitae
Fourth ventricle
Cerebellum
Medulla oblongata
Pons
Optic chiasma
Epithalamus
Mammillary body
© 2013 Pearson Education, Inc.
© 2013 Pearson Education, Inc.
Lateralization of Cortical FunctionLeft hemisphere
Controls language, math, and logic
Right hemisphere Visual-spatial skills, intuition, emotion, and artistic
and musical skills
Hemispheres communicate almost instantaneously via fiber tracts and functional integration
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Cerebral HemispheresFive lobes
Frontal Parietal Temporal Occipital Insula
Cerebral CortexThin (2–4 mm) superficial layer of gray matter
40% mass of brain
Site of conscious mind: awareness, sensory perception, voluntary motor initiation, communication, memory storage, understanding
4 General Considerations of Cerebral Cortex1. Three types of functional areas
Motor areas—control voluntary movement Sensory areas—conscious awareness of sensation Association areas—integrate diverse information
2. Each hemisphere concerned with contralateral side of body
Cerebral HemispheresCentral sulcus
Separates precentral gyrus of frontal lobe and postcentral gyrus of parietal lobe
Frontal lobe
Postcentralgyrus
Parietal lobe
CentralsulcusPrecentral
gyrus
Parieto-occipital sulcus(on medial surfaceof hemisphere)
Lateral sulcus
Temporal lobeOccipital lobe
Transversecerebral fissure
Pons
Spinal cordFissure(a deepsulcus)
Gyrus
Cortex (gray matter)
Sulcus
White matter
Lobes and sulci of the cerebrum
Medulla oblongata
Cerebellum
Primary Motor Cortex
Motor homunculi - upside-down caricatures represent contralateral motor innervation of body regions
Frontal lobeCentralsulcus
Gyri of insula
Temporal lobe(pulled down)
Location of the insula lobe
Posterior
Motor SensoryAnterior
Primary motorcortex(precentral gyrus)
Primary somato-sensory cortex(postcentral gyrus)
Motor map inprecentral gyrus
Sensory map inpostcentral gyrus
Swallowing
Tongue
Jaw
Lips
Face
Eye
Brow
Neck
Thumb
Fingers
Hand
Elb
ow
Wrist
Toes
Genitals
Arm
Sh
ou
lder
Tru
nk
Hip
Fo
ot
Kn
ee
Kn
ee
Leg Hip
Tru
nk
Ne
ck
Hea
dA
rmE
lbow
Fore
arm
Han
d
Fing
ers
Thum
b
Eye
Nose
Face
Lips
Teeth
JawGums
Tongue
Pharynx
Intra-abdominal
Primary Somatosensory Cortex
In postcentral gyri of parietal lobe
Receives general sensory information Somatosensory homunculus upside-down caricatures represent contralateral sensory input from body regions
Posterior
SensoryAnterior
Primary somato-sensory cortex(postcentral gyrus)
Sensory map inpostcentral gyrus
Genitals
Fo
ot
Kn
ee
Leg Hip
Tru
nk
Ne
ck
Hea
dA
rmE
lbow
Fore
arm
Han
d
Fing
ers
Thum
b
Eye
Nose
Face
Lips
Teeth
JawGums
Tongue
Pharynx
Intra-abdominal
Visual AreasPrimary visual (striate) cortex
Extreme posterior tip of occipital lobe Receives visual information from retinas
Motor areas
Primary motor cortex
Premotor cortexFrontaleye fieldBroca's area(outlined by dashes)
Working memoryfor spatial tasks
Executive area fortask management
Working memory for object-recall tasksSolving complex,multitask problems
Prefrontal cortex
Lateral view, left cerebral hemisphere
Sensory areas and relatedassociation areasPrimary somatosensorycortexSomatosensoryassociation cortex
Gustatory cortex(in insula)
Somatic sensation
Taste
Wernicke's area(outlined by dashes)
Primary visualcortexVisualassociation area
Auditoryassociation area
Primary auditory cortex
Vision
Hearing
Central sulcus
Primary motorcortex
Motor associationcortex
Primary sensorycortex
Sensoryassociation cortex
Multimodal associationcortex
Auditory AreasPrimary auditory cortex
Superior margin of temporal lobes Interprets information from inner ear as pitch,
loudness, and location
Motor areas
Primary motor cortex
Premotor cortexFrontaleye fieldBroca's area(outlined by dashes)
Working memoryfor spatial tasks
Executive area fortask management
Working memory for object-recall tasksSolving complex,multitask problems
Prefrontal cortex
Lateral view, left cerebral hemisphere
Sensory areas and relatedassociation areasPrimary somatosensorycortexSomatosensoryassociation cortex
Gustatory cortex(in insula)
Somatic sensation
Taste
Wernicke's area(outlined by dashes)
Primary visualcortexVisualassociation area
Auditoryassociation area
Primary auditory cortex
Vision
Hearing
Central sulcus
Primary motorcortex
Motor associationcortex
Primary sensorycortex
Sensoryassociation cortex
Multimodal associationcortex
OIfactory CortexPrimary olfactory (smell) cortex
Medial aspect of temporal lobes (in piriform lobes)
Motor areas
Primary motor cortex
Premotor cortexFrontaleye fieldBroca's area(outlined by dashes)
Working memoryfor spatial tasks
Executive area fortask management
Working memory for object-recall tasksSolving complex,multitask problems
Prefrontal cortex
Lateral view, left cerebral hemisphere
Sensory areas and relatedassociation areasPrimary somatosensorycortexSomatosensoryassociation cortex
Gustatory cortex(in insula)
Somatic sensation
Taste
Wernicke's area(outlined by dashes)
Primary visualcortexVisualassociation area
Auditoryassociation area
Primary auditory cortex
Vision
Hearing
Central sulcus
Primary motorcortex
Motor associationcortex
Primary sensorycortex
Sensoryassociation cortex
Multimodal associationcortex
Gustatory Cortex In insula just deep to temporal lobe
Involved in perception of taste
Corpuscallosum
Frontal eye field
Prefrontalcortex
Processes emotionsrelated to personaland social interactions
Orbitofrontalcortex
Olfactory bulb
Olfactory tract
FornixTemporallobe
Primaryolfactorycortex
Uncus
Calcarine sulcus
Parahippocampalgyrus
Parietal lobe
Somatosensoryassociation cortex
Parieto-occipitalsulcus
Occipitallobe
Visual associationarea
Primaryvisual cortex
Primary somatosensorycortex
Central sulcusPrimarymotor cortex
Cingulategyrus
Premotorcortex
Parasagittal view, right cerebral hemisphere
Primary motorcortex
Motor associationcortex
Primary sensorycortex
Sensoryassociation cortex
Multimodal associationcortex
Limbic System: Emotion and CognitionReact emotionally to things we consciously
understand to be happening
Consciously aware of emotional richness in our lives
Hippocampus and amygdaloid body—play a role in memory
Septum pellucidum
Fiber tracts connectinglimbic system structures
FornixAnterior commissure
Cerebral structures of the limbic system
Cingulate gyrusSeptal nucleiAmygdaloid body
Hippocampus
Diencephalic structures of the limbic system
Anterior thalamicnuclei (flanking3rd ventricle)
Hypothalamus
Mammillary body
Olfactory bulb
Corpus callosum
• Dentate gyrus• Parahippocampal gyrus
Reticular Formation: RAS and Motor Function
Reticular activating system (RAS) Sends impulses to cerebral cortex to keep it
conscious and alert Filters out repetitive, familiar, or weak stimuli
(~99% of all stimuli!) ADHD
Inhibited by sleep centers, alcohol, drugs Severe injury results in permanent
unconsciousness (coma)
Visualimpulses
Reticular formation
Ascending generalsensory tracts(touch, pain, temperature)
Descendingmotor projectionsto spinal cord
Radiationsto cerebralcortex
Auditoryimpulses
Protection of the BrainBone (skull)
Membranes (meninges)
Watery cushion (cerebrospinal fluid)
Blood brain barrier
MeningesCover and protect CNS
Protect blood vessels and enclose venous sinuses
Contains cerebrospinal fluid (CSF)
Forms partitions in skull
MeningesThree layers
Dura mater Arachnoid mater Pia mater
Meningitis Inflammation of meninges
Skin of scalpPeriosteum
Bone of skullDura mater• Periosteal layer• Meningeal layer
Arachnoid materPia materArachnoid villusBlood vessel
Falx cerebri(in longitudinalfissure only)
Superior sagittalsinus
Subduralspace
Subarachnoidspace
Dura Mater Strongest layer
Arachnoid MaterMiddle layer with weblike extensions
Separated from dura mater by subdural space
Subarachnoid space contains CSF and largest blood vessels of brain
Arachnoid villi protrude into superior sagittal sinus and permit CSF reabsorption
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Skin of scalpPeriosteum
Bone of skullDura mater• Periosteal layer• Meningeal layer
Arachnoid materPia materArachnoid villusBlood vessel
Falx cerebri(in longitudinalfissure only)
Superior sagittalsinus
Subduralspace
Subarachnoidspace
Pia MaterDelicate vascularized connective tissue that
clings tightly to brain
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