ch 16_lecture_presentation
TRANSCRIPT
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16The Nervous System: The Brain and Cranial Nerves
PowerPoint® Lecture Presentations prepared bySteven BassettSoutheast Community College Lincoln, Nebraska
© 2012 Pearson Education, Inc.
Introduction
• The brain is a complex three-dimensionalstructure that performs a bewildering array of functions
• The brain consists of roughly 20 billion neurons
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Table 16.1 Development of the Human Brain
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Figure 16.1 Major Divisions of the Brain
CEREBRUM
DIENCEPHALON
MESENCEPHALON
PONS
MEDULLA OBLONGATA
CEREBELLUM
• Coordinates complex somatic motor patterns• Adjusts output of other somatic motor centers in brain and spinal cord
Spinalcord
Brainstem
• Relays sensory information to thalamus and to other portions of the brain stem• Autonomic centers for regulation of visceral function (cardiovascular, respiratory, and digestive system activities)
• Relays sensory information to cerebellum and thalamus• Subconscious somatic and visceral motor centers
• Processing of visual and auditory data• Generation of reflexive somatic motor responses• Maintenance of consciousness
• Centers controlling emotions, autonomic functions, and hormone production
• Relay and processing centers for sensory information
THALAMUS
HYPOTHALAMUS
• Conscious thought processes, intellectual functions• Memory storage and processing• Conscious and subconscious regulation of skeletal muscle contractions
Left cerebralhemisphere
Gyri
Sulci
Fissures
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An Introduction to the Organization of the Brain
• Major Regions and Landmarks of the Brain• Medulla oblongata• Pons• Cerebellum• Mesencephalon (midbrain)• Diencephalon • Cerebrum (telencephalon)
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Figure 16.13a Sectional Views of the Brain
MesencephalonPons
Temporal lobe
Mamillary body
Optic chiasm
Anteriorcommissure
Frontal lobe
Interventricularforamen
Septumpellucidum
Corpus callosum
Precentral gyrus Central sulcus Postcentral gyrusCingulate gyrus
FornixThalamus
Membranous portionof epithalamusHypothalamus
Pineal gland
Parieto-occipitalsulcus
Superiorcolliculus
CorporaquadrigeminaInferior
colliculus
Aqueductof midbrain
Fourth ventricle
Cerebellum
Medullaoblongata
A sagittal section through the brain
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An Introduction to the Organization of the Brain
• Medulla oblongata• Relays information to the thalamus and brain
stem• Regulates visceral function
• Pons• Relays information to the thalamus and
cerebellum• Regulates subconscious somatic and visceral
motor centers
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An Introduction to the Organization of the Brain
• Cerebellum• Coordinates somatic motor function• Adjusts output of somatic motor centers
resulting in smooth operation
• Mesencephalon (midbrain)• Processes visual and auditory data• Maintains consciousness and alertness
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An Introduction to the Organization of the Brain
• Diencephalon• Epithalamus
• Contains the pineal gland
• Thalamus• Relays information to the cerebrum• Processes sensory information
• Hypothalamus• Involved in emotions, thirst, some habitual activity
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An Introduction to the Organization of the Brain
• Telencephalon (cerebrum)• Conscious thought processes• Memory storage• Conscious regulation of skeletal muscle
contractions
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Figure 16.1 Major Divisions of the Brain
CEREBRUM
DIENCEPHALON
MESENCEPHALON
PONS
MEDULLA OBLONGATA
CEREBELLUM
• Coordinates complex somatic motor patterns• Adjusts output of other somatic motor centers in brain and spinal cord
Spinalcord
Brainstem
• Relays sensory information to thalamus and to other portions of the brain stem• Autonomic centers for regulation of visceral function (cardiovascular, respiratory, and digestive system activities)
• Relays sensory information to cerebellum and thalamus• Subconscious somatic and visceral motor centers
• Processing of visual and auditory data• Generation of reflexive somatic motor responses• Maintenance of consciousness
• Centers controlling emotions, autonomic functions, and hormone production
• Relay and processing centers for sensory information
THALAMUS
HYPOTHALAMUS
• Conscious thought processes, intellectual functions• Memory storage and processing• Conscious and subconscious regulation of skeletal muscle contractions
Left cerebralhemisphere
Gyri
Sulci
Fissures
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An Introduction to the Organization of the Brain
• The Ventricles of the Brain• Ventricles are fluid-filled cavities
• Filled with cerebrospinal fluid (CSF)
• Fluid transports nutrients to the CNS and transports waste away from the CNS
• CSF also provides protection
• There are four ventricles• Ventricles 1 and 2 (called lateral ventricles) are in the
cerebral hemispheres (separated by a partition called the septum pellucidum)
• Ventricle 3 is in the diencephalon
• Ventricle 4 lies between the pons and the cerebellum
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Figure 16.2a Ventricles of the Brain
Orientation and extent of the ventricles asseen in a lateral view of a transparent brain
Anteriorhornsof lateralventricles
Cerebralhemispheres
Pons
Medulla oblongata
Central canalSpinal cord
Lateral ventricles
Interventricularforamen
Third ventricle
Posterior horns oflateral ventricles
Inferior horns oflateral ventricles
Aqueduct ofmidbrain
Fourthventricle
Cerebellum
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Figure 16.2c Ventricles of the Brain
Anterior view of the ventricles as ifseen through a transparent brain
Thirdventricle
Aqueduct ofmidbrain
Fourthventricle
Cerebellum
Central canal
Medulla oblongata
Pons
Interventricularforamen
Longitudinalfissure
Lateral ventricles incerebral hemispheres
Inferior horns oflateral ventricles
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Figure 16.2d Ventricles of the Brain
Diagrammatic coronal section showing theinterconnections between the ventricles
Lateral ventricles
Interventricularforamen
Thirdventricle
Inferior horn oflateral ventricle
Aqueduct ofmidbrain
Fourthventricle
Septumpellucidum
Central canal
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Protection and Support of the Brain
• Protection involves:• Bones of the skull
• Parietal, frontal, occipital, and temporal bones
• Cranial meninges• Dura mater, arachnoid mater, and pia mater
• Cerebrospinal fluid• CSF is produced by choroid plexus in the brain
ventricles.• CSF is drained at arachnoid granulation into the
dural sinuses.
• Blood–brain barrier
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Figure 16.3a Relationships among the Brain, Cranium, and Meninges
Lateral view of the brainshowing its position in thecranium and the organizationof the meningeal coverings
Spinal cord
Medulla oblongata
Cerebellum
Cerebralcortex
Cerebralcortex
Piamater
Subarachnoidspace
Cranium Dura mater(endosteal layer)
Dural sinus
Dura mater(meningeal layer)
Subdural space
Arachnoidmater
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Figure 16.3b Relationships among the Brain, Cranium, and Meninges
A corresponding view of the cranial cavity with thebrain removed showing the orientation and extentof the falx cerebri and tentorium cerebelli
Diaphragma sellae
Pituitary gland
Sella turcicaof sphenoid
Inferior sagittal sinus
Dura mater
Superior sagittal sinus
Cranium
Falx cerebri
Tentoriumcerebelli
Transversesinus
Falx cerebelli
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Figure 16.5a The Cranial Meninges, Part II
Coronal section
This view shows the organization and relationshipof the cranial meninges to the brain.
Arachnoidmater
ArachnoidtrabeculaePia mater
Dura mater
Cerebral cortex
Falx cerebri
Subarachnoidspace
Arachnoidgranulation
Subduralspace
Superior sagittalsinus
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Figure 16.5b The Cranial Meninges, Part II
Coronal section
A detailed view of the arachnoid membrane, thesubarachnoid space, and the pia mater. Note therelationship between the cerebral vein and thesubarachnoid space.
Arachnoid mater
Arachnoidtrabecula
Cerebralvein
Perivascularspace
Pia materCerebralcortex
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Protection and Support of the Brain
• Cerebrospinal Fluid (CSF)• Provides protection of the brain and spinal cord• Provides support• Transports nutrients to the CNS tissue• Transports waste away from the CNS
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Figure 16.6 The Choroid Plexus and Blood–Brain Barrier
INTERSTITIAL FLUID IN THALAMUS
The location of the choroid plexus ineach of the four ventricles of the brain
The structure and function of thechoroid plexus. The ependymalcells are a selective barrier, actively transporting nutrients, vitamins, and ions into the CSF. Whennecessary, these cells also activelyremove ions or compounds fromthe CSF to stabilize its composition. CEREBROSPINAL FLUID IN THIRD VENTRICLE
CHOROID PLEXUS
Tight junction
Ions(Na, K, Cl, HCO3
, Ca2, Mg2)VitaminsOrganic nutrientsOxygen
Waste productsIonsAmino acids(when necessary)
Choroidplexuscells
Capillary
CO2
Waste products
Tightjunction Astrocyte Neuron
Blood–brainbarrier
Capillary
Endothelial cell
Ependymalcells
Nutrients(especially glucose)Oxygen
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Protection and Support of the Brain
• Circulation of CSF• CSF from the choroid plexus of the lateral ventricles• Flows through the interventricular foramen• Flows into the third ventricle• Flows into the aqueduct of the midbrain• Flows into the fourth ventricle• Through the lateral aperture and median aperture and
central canal of the spinal cord• Flows into the subarachnoid space• Flows around the brain and spinal cord eventually
enters circulation via the arachnoid granulations
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Figure 16.7 Circulation of Cerebrospinal Fluid
Dura mater
Filumterminale
Spinalcord
Centralcanal
Subarachnoid space
Arachnoid mater
Median aperture
Choroid plexus offourth ventricle
Lateral aperture
Aqueductof midbrain
Choroid plexusof third ventricle
Extension of choroidplexus into
lateral ventricle
Arachnoidgranulations
Superiorsagittalsinus
Piamater
Subarachnoidspace
Cerebralcortex
Superiorsagittal sinus Cranium Dura mater
(endosteallayer)
Arachnoidgranulation
Fluidmovement
Arachnoidtrabecula
Dura mater(meningeallayer)
Subdural space
Arachnoidmater
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The Medulla Oblongata
• Medulla oblongata • Continuous with the spinal cord to the brain
stem• All communication between the brain and spinal
cord passes through the medulla oblongata
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The Medulla Oblongata
• Nuclei of cranial nerves• Contains sensory and motor nuclei of cranial
nerves:• VIII, IX, X, XI, and XII
• Autonomic nuclei• Major centers include:
• Cardiovascular centers (cardiac and vasomotor)• Respiratory centers (rhythmic breathing)
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Figure 16.8a The Medulla Oblongata
Anterior view
PyramidsOlive
Medullaoblongata
Pons
Spinal cord
Olivary nucleus
Cardiovascularcenters
Solitary nucleus
Nucleus cuneatus
Nucleus gracilis
Reticular formation
Lateral white column
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Figure 16.8b The Medulla Oblongata
PyramidsOlive
Pons
Posterolateral view
Spinal cord
Olivary nucleus
Cardiovascularcenters
Respiratoryrhythmicity center
Solitary nucleus
Nucleus cuneatus
Nucleus gracilis
Reticular formation
Lateral white column
Attachment tomembranousroof of fourthventricle
Posteriormedian sulcus
Posteriorwhite columns
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The Pons
• The pons is a prominent bulge superior tothe medulla oblongata and consists of:
• Sensory and motor nuclei for cranial nerves:• V, VI, VII, and VIII
• Nuclei involved with involuntary control of breathing:
• Consist of apneustic center and pneumotaxic center
• Nuclei that relay cerebellar commands:• Consist of cerebellar peduncles
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Figure 16.9 The Pons
Olivarynucleus
Medullaoblongata
Transversefibers
Ascendingtracts
Pons
Descending tracts
Pneumotaxiccenter
Apneusticcenter
Cerebellum
Fourthventricle
Reticularformation
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The Mesencephalon
• Mesencephalon (also called the midbrain)• Consists of two pairs of nuclei collectively called
corpora quadrigemina• Responsible for processing auditory and visual
stimuli• Auditory processing occurs in the inferior colliculus• Visual processing occurs in the superior colliculus
• Consists of nuclei of the reticular formation• Involved in maintaining alertness
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The Mesencephalon
• Mesencephalon (continued)• Consists of:
• Red nucleus: integrates information between the cerebrum and cerebellum
• Substantia nigra: regulates motor output of the basal nuclei
• Cerebral peduncles: have ascending fibers that synapse in the thalamus and descending fibers of the corticospinal pathway
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Figure 16.10b The Mesencephalon
Diagrammatic and posterior views of the diencephalonand brain stem. The diagrammatic view is drawn, as iftransparent, to show the positions of important nuclei.
Superiorcolliculi
Inferiorcolliculi
Corporaquadrigemina
Trochlearnerve (N IV)
Cerebralpeduncle
Superiorcerebellarpeduncle
Reticular formationin floor of
fourth ventricle
Fourth ventricle
Pinealgland
Superiorcolliculus
Cerebralpeduncle
Thalamus
Red nucleus
Substantianigra
Inferiorcolliculus
Reticular formation
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The Diencephalon
• The diencephalon consists of:• Epithalamus• Thalamus • Hypothalamus
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Figure 16.12a The Hypothalamus
Midsagittal section through the brain. This view shows the major featuresof the diencephalon and adjacent portions of the brain stem.
Opticnerve
Infundibulum(cut)
Tuberalarea
Mamillarybody
Corpuscallosum
Septumpellucidum
Fornix
Anteriorcerebral artery
Frontal lobe
Anteriorcommissure
Optic chiasm
Parietallobe
Choroid plexusin epithalamus
Thalamus(surroundsthird ventricle)
Pineal gland
Aqueduct ofmidbrain
Hypothalamus
Cerebellum
Fourthventricle
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The Diencephalon
• The epithalamus• Forms the roof of the third ventricle• Contains the pineal gland
• Produces the hormone melatonin• Regulates our day/night cycles
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The Diencephalon
• The thalamus• Forms the walls of the third ventricle
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Figure 16.11a The Thalamus
Lateral view of the brain showing thepositions of the major thalamicstructures. Functional areas of cerebral cortex are also indicated,with colors corresponding to those ofthe associated thalamic nuclei.
Occipitallobe
Parietal lobeFrontallobe
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Figure 16.11b The Thalamus
Enlarged view of the thalamic nuclei of the left side. The color ofeach nucleus or group of nuclei matches the color of the associatedcortical region. The boxes either provide examples of the types ofsensory input relayed to the basal nuclei and cerebral cortex orindicate the existence of important feedback loops involved withemotional states, learning, and memory.
Cerebellum
Basalnuclei
Generalsensory
inputVisualinput
Auditoryinput
Limbicsystem
Frontallobes
Parietal lobe andcingulate gyrus
Association areasof cerebral cortex
Lateralgeniculatenucleus
Medialgeniculatenucleus
Pulvinar
Medial group
Lateral group
Anterior group
Posteriorgroup
V e n t r a lg r o u p
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The Diencephalon
• The hypothalamus• Forms the floor of the third ventricle• Consists of numerous nuclei• Consists of an infundibulum, which connects
to the pituitary gland
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The Diencephalon
• The hypothalamus (continued)• Consists of nuclei to control:
• Subconscious control of skeletal muscles• Heart rate, blood pressure, respiration, and digestive
functions• Secretion of antidiuretic hormone and oxytocin• Emotional and behavioral drives and thirst drives• Coordination between voluntary and autonomic
functions• Body temperature• Circadian rhythm
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Figure 16.12a The Hypothalamus
Midsagittal section through the brain. This view shows the major featuresof the diencephalon and adjacent portions of the brain stem.
Opticnerve
Infundibulum(cut)
Tuberalarea
Mamillarybody
Corpuscallosum
Septumpellucidum
Fornix
Anteriorcerebral artery
Frontal lobe
Anteriorcommissure
Optic chiasm
Parietallobe
Choroid plexusin epithalamus
Thalamus(surroundsthird ventricle)
Pineal gland
Aqueduct ofmidbrain
Hypothalamus
Cerebellum
Fourthventricle
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Figure 16.12b The Hypothalamus
Enlarged view of the hypothalamus showing the locations of major nuclei andcenters. Functions for these centers are summarized in Table 16.6.
Thalamus
Hypothalamus
Pons
Tuberalarea
Mamillarybody
Posterior lobe ofpituitary gland(pars nervosa)
Autonomic centers(sympathetic)
Paraventricularnucleus
Preoptic area
Autonomic centers(parasympathetic)
Suprachiasmaticnucleus
Anteriorlobe of
pituitarygland
Supraoptic nucleus
Tuberal nuclei
Optic chiasm
Infundibulum
Pars distalis
Pars intermedia
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The Cerebellum
• The cerebellum consists of:• Two hemispheres• Folia (folds similar to gyri of the cerebrum)• Anterior and posterior lobes• Vermis (separates the hemispheres)• Flocculonodular lobes• Arbor vitae• Cerebellar peduncles
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Figure 16.15b The Cerebellum
Dendrites projectinginto the gray matter
of the cerebellum
Axons of Purkinje cellsprojecting into the whitematter of the cerebellum Purkinje cells LM 120
Cell body of Purkinje cell
Sagittal view of the cerebellum showing the arrangement of gray matterand white matter. Purkinje cells are seen in the photomicrograph; theselarge neurons are found in the cerebellar cortex.
Cerebellarpeduncles
SuperiorMiddle
Inferior
Medulla oblongata
Pons
Anterior lobe
Arborvitae
Cerebellarnucleus
Cerebellarcortex
Posterior lobe
Flocculonodular lobe
Choroid plexus ofthe fourth ventricle
Medullaoblongata
Fourthventricle
Mamillarybody
Pons
Superior colliculus
Aqueduct of midbrain
Inferior colliculus
Anterior lobe
Arbor vitae
Cerebellar cortex
Cerebellarnucleus
Posteriorlobe
Flocculonodular lobe
Mesencephalon
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Figure 16.15a The Cerebellum
Superior surface of the cerebellum. This viewshows major anatomical landmarks and regions.
Left hemisphereof cerebellum
Right hemisphereof cerebellum
Folia
Folia
Vermis Vermis
Cerebellum
Anterior lobe
Primary fissure
Posterior lobe
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The Cerebellum
• The cerebellum• Cerebellar cortex: subconscious coordination
of movements• Arbor vitae: connects cerebellar cortex with
cerebellar peduncles
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The Cerebrum
• The cerebrum consists of:• Two hemispheres• Several lobes
• Frontal, parietal, occipital, and temporal
• Gyri and sulci• Longitudinal fissure• Corpus callosum• Basal nuclei• Limbic system
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The Cerebrum
The cerebrum is the largest, most superior portion of the human brain. Each cerebral hemisphere receives sensory information from and generates motor commands to the opposite side of the body. The two hemispheres have some functional differences, although anatomically they appear to be identical. The cerebral hemispheres are separated by longitudinal fissure.Cortical surface of the brain forms a series of grooves called sulci.
The sulcus between frontal and parietal lobe is central sulcus. This sulcus functionally separates the sensory and motor part of cerebrum.The sulcus between parietal and temporal lobe id lateral sulcus.The eminence between two sulsi is called gyrus.
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Figure 16.16a The Cerebral Hemispheres, Part I
Superior view
POSTERIOR
ANTERIOR
Right cerebralhemisphere
Cerebral veins andarteries covered byarachnoid mater
Central sulcus
Parieto-occipitalsulcus
Cerebellum
Left cerebralhemisphere
Longitudinalfissure
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The Cerebrum
• The Cerebral Hemispheres• The Cerebral Lobes
• Frontal lobe: conscious control of skeletal muscles• Occipital lobe: perception of visual stimuli• Parietal lobe: conscious perception of touch,
pressure, vibration, pain, temperature, and taste• Temporal lobe: conscious perception of auditory and
olfactory stimuli
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Figure 16.17a The Cerebral Hemispheres, Part II
Lateral view of intact brain after removal of thedura mater and arachnoid mater showingsuperficial surface anatomy of the left hemisphere
Precentral gyrus
Central sulcus
Lateral sulcus
FRONTAL LOBEof left cerebral
hemisphere
Branches of middlecerebral artery emerging
from lateral sulcus
TEMPORAL LOBE
Medulla oblongata
Pons
Cerebellum
OCCIPITAL LOBE
PARIETAL LOBE
Postcentralgyrus
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Figure 16.13a Sectional Views of the Brain
MesencephalonPons
Temporal lobe
Mamillary body
Optic chiasm
Anteriorcommissure
Frontal lobe
Interventricularforamen
Septumpellucidum
Corpus callosum
Precentral gyrus Central sulcus Postcentral gyrusCingulate gyrus
FornixThalamus
Membranous portionof epithalamusHypothalamus
Pineal gland
Parieto-occipitalsulcus
Superiorcolliculus
CorporaquadrigeminaInferior
colliculus
Aqueductof midbrain
Fourth ventricle
Cerebellum
Medullaoblongata
A sagittal section through the brain
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The Cerebrum
• Hemispheric Specialization• Left hemisphere
• Speech center, writing, language, mathematics
• Right hemisphere• Analysis by touch, spatial visualization
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Figure 16.18 Hemispheric Specialization
LEFT HAND
Prefrontalcortex
Speech center
Writing
Auditory cortex(right ear)
General interpretivecenter (language
and mathematicalcalculation)
Visual cortex(right visual field)
LEFTHEMISPHERE
RIGHTHEMISPHERE
CORPUS
CALLOSUM
RIGHT HAND
Prefrontalcortex
Anterior commissure
Auditory cortex(left ear)
Analysisby touch
Spatialvisualizationand analysis
Visual cortex(left visual field)
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The Cerebrum
• The Central White Matter• Consists of bundles called:
• Association fibers: tracts that interconnect areas of neural cortex within a hemisphere (arcuate fibers and longitudinal fasciculi)
• Commissural fibers: tracts that connect the two hemispheres (anterior commissure and corpus callosum)
• Projection fibers: tracts that link the cerebrum with other regions of the brain and spinal cord
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Figure 16.19a The Central White Matter
Lateral aspect of the brain showingarcuate fibers and longitudinal fasciculi
Arcuate fibers
Longitudinalfasciculi
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Figure 16.19b The Central White Matter
Anterior view of the brain showing orientationof the commissural and projection fibers
Anterior commissure
Projection fibers ofinternal capsule
Corpuscallosum
Longitudinalfissure
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The Cerebrum
• The Basal Nuclei• These are masses of gray matter embedded in
the white matter inferior to the lateral ventricles• Consist of:
• Caudate nucleus• Putamen• Globus pallidus• Claustrum• Amygdaloid body
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The Cerebrum
• The Basal Nuclei• Caudate nucleus, putamen, and globus
pallidus• Control the cycles of arm and leg movements when
walking
• Claustrum• Plays a role in subconscious processing of visual
information. It focuses attention on specific patterns or relevant features (watching movie!)
• Amygdaloid body• Component of the limbic system
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Figure 16.20c The Basal Nuclei
Frontal section
Head of caudatenucleus
Lateralventricle
Claustrum
Insula
Putamen
Lentiformnucleus
Globuspallidus
Amygdaloid body
Corpus callosum
Septum pellucidum
Internal capsule
Lateral sulcus
Anterior commissure
Tip of inferior horn oflateral ventricle
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The Cerebrum
• The Limbic System• Located between the cerebrum and the
diencephalon just superior to the corpus callosum
• Functions:• Establishes emotional states• Links the conscious functions with the unconscious
autonomic functions• Facilitates memory storage and retrieval
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Figure 16.21a The Limbic System
Sagittal section through the cerebrum showing the corticalareas associated with the limbic system. The parahippocampaland dentate gyri are shown as if transparent so that deeperlimbic components can be seen.
ThalamusHypothalamus
Temporal lobe
Parahippocampalgyrus (limbic lobe) Hippocampus
(within dentate gyrus)Mamillary
body
Corpuscallosum
Interthalamicadhesion
Centralsulcus
Cingulate gyrus(limbic lobe)
Fornix
Pineal gland
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The Cerebrum
• The Limbic System• The fornix
• Tract of white matter connecting the hippocampus with the hypothalamus
• Many fornix fibers extend to the mamillary bodies• Mamillary bodies control reflex movements
associated with eating
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The Cranial Nerves
• There are 12 pairs of cranial nerves• These nerves innervate the periphery emerging
from the brain (not the spinal cord)• These nerves are on the ventrolateral surface of
the brain• They are numbered beginning at the anterior
aspect of the brain• They are numbered CN I to CN XII
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Figure 16.22b Origins of the Cranial Nerves
Diagrammatic inferior view of the humanbrain. Compare view with part (a).
Olfactory bulb, terminationof olfactory nerve (N I)
Olfactory tract
Optic chiasm
Optic nerve (N II)
Infundibulum
Oculomotor nerve (N III)
Trochlear nerve (N IV)
Trigeminal nerve (N V)
Abducens nerve (N VI)
Facial nerve (N VII)
Vestibulocochlearnerve (N VIII)
Glossopharyngealnerve (N IX)
Vagus nerve (N X)
Hypoglossal nerve (N XII)
Accessory nerve (N XI)
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The Cranial Nerves
• CN I: The Olfactory Nerve• Function: sensory (smell)• Origin: olfactory epithelium• Foramen: olfactory foramina• Destination: olfactory bulbs
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Figure 16.23 The Olfactory Nerve
Olfactorynerve fibers
Olfactory epithelium
Cribriform plateof ethmoid
OLFACTORYNERVE (N I)
Olfactory tract(to olfactory cortex
of cerebrum)
Left olfactory bulb(termination of
olfactory nerve)
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The Cranial Nerves
• CN II: The Optic Nerve• Function: sensory (vision)• Origin: retina • Foramen: optic canal• Destination: diencephalon, then to occipital
lobe
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Figure 16.24 The Optic Nerve
OPTIC NERVE(N II)
Mesencephalon(cut)
Optic chiasm
Optic tract
Eye
Visual cortex(in occipital lobes)
Opticprojectionfibers
Lateralgeniculatenucleus(in thalamus)
Pituitarygland
Olfactory tract
Olfactory bulb
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The Cranial Nerves
• CN III: The Oculomotor Nerve• Function: controls extra-ocular eye muscles
• Motor function• Superior, inferior, and medial rectus• Inferior oblique• Levator palpebrae superioris
• Origin: mesencephalon• Foramen: superior orbital fissure• Destination: extra-ocular eye muscles
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Figure 16.25 Cranial Nerves Controlling the Extra–Ocular Muscles
Trigeminalnerve (N V), cut
Vestibulocochlearnerve (N VIII), cut
Facial nerve(N VII), cut
ABDUCENSNERVE (N VI)
Lateralrectusmuscle
(cut)
Medialrectusmuscle
Inferiorrectusmuscle
Ciliaryganglion
OPTICNERVE (N II)
Opticchiasm
OCULOMOTORNERVE (N III)
TROCHLEARNERVE (N IV)
SuperiorrectusmuscleSuperior
obliquemuscle
Trochlea
Levatorpalpebraesuperioris
muscle
Inferiorobliquemuscle
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The Cranial Nerves
• CN IV: The Trochlear Nerve• Function: controls extra-ocular eye muscles
• Motor function• Superior oblique
• Origin: mesencephalon• Foramen: superior orbital fissure• Destination: extra-ocular eye muscles
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Figure 16.25 Cranial Nerves Controlling the Extra–Ocular Muscles
Trigeminalnerve (N V), cut
Vestibulocochlearnerve (N VIII), cut
Facial nerve(N VII), cut
ABDUCENSNERVE (N VI)
Lateralrectusmuscle
(cut)
Medialrectusmuscle
Inferiorrectusmuscle
Ciliaryganglion
OPTICNERVE (N II)
Opticchiasm
OCULOMOTORNERVE (N III)
TROCHLEARNERVE (N IV)
SuperiorrectusmuscleSuperior
obliquemuscle
Trochlea
Levatorpalpebraesuperioris
muscle
Inferiorobliquemuscle
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The Cranial Nerves
• CN V: The Trigeminal Nerve• Function:
• Mixed (sensory and motor) function• Ophthalmic: sensations from the forehead, eyelids,
and nose• Maxillary: sensations from lower eyelid, upper lip, and
cheek• Mandibular: controls mastication
• Origin: ophthalmic, maxillary, and mandibular nerves
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The Cranial Nerves
• CN V: The Trigeminal Nerve (continued)• Foramen:
• Ophthalmic: superior orbital fissure• Maxillary: foramen rotundum• Mandibular: foramen ovale
• Destination: • Ophthalmic and maxillary: Pons• Mandibular: mandibular muscles
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Figure 16.26 The Trigeminal Nerve
TRIGEMINALNERVE (N V)
Maxillarybranch
Foramen ovale
Pons
Otic ganglion
Mandibular branch
Pterygopalatineganglion
Ophthalmicbranch
Semilunarganglion
Superiororbitalfissure
Supraorbitalnerves
Ciliary ganglion
Foramenrotundum
Infra-orbitalnerve
Lingual nerve
Submandibular ganglion
Mental nerve
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The Cranial Nerves
• CN VI: The Abducens Nerve • Function: controls eye movements
• Motor function
• Origin: pons• Foramen: superior orbital fissure• Destination: innervates the lateral rectus eye
muscle
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Figure 16.25 Cranial Nerves Controlling the Extra–Ocular Muscles
Trigeminalnerve (N V), cut
Vestibulocochlearnerve (N VIII), cut
Facial nerve(N VII), cut
ABDUCENSNERVE (N VI)
Lateralrectusmuscle
(cut)
Medialrectusmuscle
Inferiorrectusmuscle
Ciliaryganglion
OPTICNERVE (N II)
Opticchiasm
OCULOMOTORNERVE (N III)
TROCHLEARNERVE (N IV)
SuperiorrectusmuscleSuperior
obliquemuscle
Trochlea
Levatorpalpebraesuperioris
muscle
Inferiorobliquemuscle
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The Cranial Nerves
• CN VII: The Facial Nerve • Function: Mixed (sensory and motor)
• Sensory: sensations from the face / taste • Motor: controls muscles of the face
• Origin: • Sensory: taste buds• Motor: pons
• Foramen: internal acoustic meatus• Destination:
• Sensory: pons• Motor: muscles of the face
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Figure 16.27a The Facial Nerve
Origin and branches of the facialnerve
Posterior auricularbranch
Stylomastoidforamen
Chorda tympani nerve(with mandibularbranch of N V)
Lingual branch(with lingual nerveof N V)
Submandibular ganglion
Pons
Pterygopalatineganglion
Greaterpetrosal
nerve
Geniculateganglion
FACIALNERVE (N VII)
Temporalbranch
Zygomaticbranches
Buccalbranch
Mandibularbranch
Cervicalbranch
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The Cranial Nerves
• CN VIII: The Vestibulocochlear Nerve • Function:
• Sensory: balance and hearing
• Origin: receptors of the vestibule and cochlea• Foramen: internal acoustic meatus• Destination: pons
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Figure 16.28 The Vestibulocochlear Nerve
Tympaniccavity
(middle ear)Semicircular
canals
Vestibularbranch(N VIII)
Facialnerve
(N VII), cut
Internalacoustic
canalVESTIBULOCOCHLEAR
NERVE (N VIII)
Pons
N V
N VIN VII
N IXN XIIN X
N XI
Medullaoblongata
Cochlearbranch (N VIII)
CochleaAuditorytube
Tympanicmembrane
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The Cranial Nerves
• CN IX: The Glossopharyngeal Nerve • Function: Mixed (sensory and motor)
• Sensory function: taste of posterior 1/3 of tongue.• Motor function: swallowing
• Origin: • Sensory: posterior 1/3 of the tongue• Motor: salivary gland
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The Cranial Nerves
• CN IX: The Glossopharyngeal Nerve (continued)
• Foramen: jugular foramen• Destination:
• Sensory: pons• Visceral motor: parotid salivary gland• Somatic motor: pharyngeal muscles for swallowing
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Figure 16.29 The Glossopharyngeal Nerve
Common carotid artery
Carotid sinus
Carotid body
Lingual branch
Otic ganglion
Inferior (petrosal)ganglion
GLOSSOPHARYNGEALNERVE (N IX)
Superior (jugular)ganglion
Pharyngeal branches
Carotid sinusbranch
Parotid salivarygland
Medulla oblongata
Pons
N VII
N VI
N V
N VIII
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The Cranial Nerves
• CN X: The Vagus Nerve • Function:
• Sensory: information from organs• Motor: sends information to the organs
• Origin: • Sensory: from the organs• Motor: medulla oblongata
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The Cranial Nerves
• CN X: The Vagus Nerve (continued) • Foramen: jugular foramen• Destination:
• Sensory: autonomic centers of the medulla oblongata• Somatic motor: muscles of the palate and pharynx• Visceral motor: respiratory, cardiovascular, and
digestive organs
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Figure 16.30 The Vagus Nerve
Superiorpharyngeal
branch
Superiorlaryngeal nerve
Recurrentlaryngeal nerve
Internal branch
External branch
VAGUSNERVE (N X)
Inferiorganglion of
vagus nerve
Cardiac branches
Cardiac plexus
Anteriorvagal trunk
Left lungRight lung
Liver
Stomach
Colon
Pancreas
Spleen
Small intestine
Celiacplexus
Hypogastricplexus
Medulla oblongata
Auricular branchto external ear
Superior ganglionof vagus nerve
Pharyngeal branch
Superior laryngeal nerve
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The Cranial Nerves
• CN XI: The Accessory Nerve • Function:
• Motor: controls the sternocleidomastoid, trapezius, palate, pharynx, and larynx muscles
• Origin: spinal cord and medulla oblongata • Foramen: jugular foramen• Destination:
• Internal branch: muscles of the palate, pharynx, and larynx
• External branch: sternocleidomastoid and trapezius muscles
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Figure 16.31 The Accessory and Hypoglossal Nerves
HYPOGLOSSAL NERVE (N XII)
ACCESSORY NERVE (N XI)
Internal branch: to palatal,pharyngeal, and laryngealmuscles with vagus nerve
Intrinsic musclesof tongue
Styloglossus muscle
Genioglossus muscle
Geniohyoid muscle
Hyoglossus muscle
Hyoid bone
Thyrohyoid muscle
Sternohyoid muscle
Sternothyroid muscle
Omohyoid muscle
Sternocleidomastoid muscle
Trapezius muscle
Ansa cervicalis(cervical plexus)
Spinal cord
External branch of N XI
Spinal root of N XI
Cranial root of N XI
Trigeminal nerve (N V)
Medulla oblongata
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The Cranial Nerves
• CN XII: The Hypoglossal Nerve • Function:
• Motor: controls tongue movement
• Origin: medulla oblongata • Foramen: hypoglossal canal• Destination: tongue muscles
© 2012 Pearson Education, Inc.
Figure 16.31 The Accessory and Hypoglossal Nerves
HYPOGLOSSAL NERVE (N XII)
ACCESSORY NERVE (N XI)
Internal branch: to palatal,pharyngeal, and laryngealmuscles with vagus nerve
Intrinsic musclesof tongue
Styloglossus muscle
Genioglossus muscle
Geniohyoid muscle
Hyoglossus muscle
Hyoid bone
Thyrohyoid muscle
Sternohyoid muscle
Sternothyroid muscle
Omohyoid muscle
Sternocleidomastoid muscle
Trapezius muscle
Ansa cervicalis(cervical plexus)
Spinal cord
External branch of N XI
Spinal root of N XI
Cranial root of N XI
Trigeminal nerve (N V)
Medulla oblongata
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The Cranial Nerves
• Summary of Cranial Nerve Branches and Functions
• Mnemonic aid• Oh, Once One Takes The Anatomy Final, Very Good
Vacations Are Heavenly
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Table 16.12 The Cranial Nerves (Part 1 of 2)
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Table 16.12 The Cranial Nerves (Part 2 of 2)