EXERCISE 17: EXERCISE 17:

BRAIN AND CRANIAL BRAIN AND CRANIAL NERVESNERVES

http://www.vision.caltech.edu/feifeili/101_ObjectCategories/brain/image_0026.jpg

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Figure 17-1 Embryonic development of the human brain.

Neuraltube(containsneuralcanal)

Primary brain vesicles Secondary brain vesicles Adult brainstructures

Adult neuralcanal regions

Anterior(rostral)

Posterior(caudal)

Prosencephalon(forebrain)

Mesencephalon(midbrain)

Rhombencephalon(hindbrain)

Cerebrum: cerebralhemispheres (cortex,white matter, basal nuclei)

Diencephalon(thalamus, hypothalamus,epithalamus), retina

Brain stem: midbrain

Brain stem: pons

Cerebellum

Brain stem: medullaoblongata

Spinal cord Central canal

Fourth ventricle

Cerebral aqueduct

Third ventricle

Lateral ventricles

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FOREBRAINFOREBRAIN

MIDBRAINMIDBRAIN

HINDBRAINHINDBRAIN

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Figure 17-2a External features of the cerebral hemispheres.

Frontal lobe

Precentral gyrusCentral sulcus

Postcentral gyrus

Parietal lobe

Occipital lobe

Temporal lobe

Transversecerebral fissure

CerebellumPons

Medulla oblongata

Gyrus

Sulcus

Fissure(a deep sulcus)

White matter

Cortex(gray matter)

Spinal cord

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Figure 17-2b External features of the cerebral hemispheres.

AnteriorFrontal lobe

Longitudinalfissure

Precentralgyrus

Central sulcus

Postcentralgyrus

Posterior

Parietal lobe

Occipital lobe

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Figure 17-2c External features of the cerebral hemispheres.

Frontal lobe

Longitudinalfissure

Precentralgyrus

Central sulcus

Postcentralgyrus

Parietal lobe

Occipital lobe

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Figure 17-2d External features of the cerebral hemispheres.

Central sulcusMotor areas

Primary motor cortex

Prefrontal cortex

Sensory areas and relatedassociation areas

Primary somatosensorycortexSomatosesoryassociation cortex

Somaticsensation

Taste

Vision

Hearing

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Figure 17-3 Ventral (inferior) aspect of the human brain, showing the three regions of the brain stem. (2 of 3)

Frontal lobe

Olfactory bulb

Olfactory tract

Optic chiasma

Optic nerve

Optic tract

Midbrain

Pons

Medullaoblongata

Temporal lobe

Cerebellum

Spinal cord

Cerebralpeduncleof midbrain

Pituitarygland

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Figure 17-3 Ventral (inferior) aspect of the human brain, showing the three regions of the brain stem. (3 of 3)

Frontal lobe

Olfactory bulb

Olfactory tract

Optic chiasma

Optic nerve

Optic tract

Midbrain

Pons

Medullaoblongata

Temporal lobe

Cerebellum

Spinal cord

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Figure 17-4a Diencephalon and brain stem structures as seen in a sagittal section of the brain.

Lateral ventricle

Hypothalamus

Corpus callosum

Optic chiasma

Pons

Medulla oblongata

Fourth ventricle

Cerebellum

Arbor vitae

Corporaquadrigemina

SuperiorcolliculiInferiorcolliculi

Pineal gland

Thalamus

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Figure 17-4b Diencephalon and brain stem structures as seen in a sagittal section of the brain.

Cerebral hemisphere

Optic chiasma

Pituitary gland

Hypothalamus

Pons

Medullaoblongata

Spinal cord

Cerebellum

Choroid plexus

Fourth ventricle

Arbor vitae (of cerebellum)

Corporaquadrigemina

Cerebralaqueduct

Midbrain

Pineal gland

Thalamus(encloses third ventricle)

Choroid plexus

Corpus callosum

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Figure 17-5b Basal nuclei.

Cerebral cortex

Cerebral white matter

Corpus callosum

Anterior hornof lateral ventricle

Thalamus

Third ventricle

Inferior hornof lateral ventricle

Posterior

Anterior

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CEREBRUM

Transverse Fissure

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ON FRONTAL LOBE ON FRONTAL LOBE Primary motor areaPrimary motor area

ON ON PARIETAL PARIETAL

LOBE LOBE Primary Primary somato-somato-sensory sensory

areaarea

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Cortex (superficial) is gray matterCortex (superficial) is gray matterWhite matter is deeperWhite matter is deeper

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DIENCEPHALON= thalamus + DIENCEPHALON= thalamus + hypothalamushypothalamus

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Pineal Gland

Endocrine Endocrine AttachmentsAttachments

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MENINGESMENINGES

Same setup as Same setup as spinal cord—spinal cord—

Dura mater most Dura mater most superficial,superficial,

Arachnoid,Arachnoid,

Pia mater closest Pia mater closest to brainto brain

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• Mesencephalic or CEREBRAL aqueduct

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CHOROID PLEXUSESCHOROID PLEXUSES

Specialized capillaries in Specialized capillaries in ventriclesventricles

Produce CSF—Circulates Produce CSF—Circulates from here to central canal (s. from here to central canal (s. cord) & around outside of cord) & around outside of brain/cord toobrain/cord too

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MIDBRAINMIDBRAIN

CORPORA CORPORA QUADRIGEMINAQUADRIGEMINA

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HINDBRAINHINDBRAIN

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HINDBRAIN--HINDBRAIN--cerebellumcerebellum

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Sensory Nerve Sensory Nerve AttachmentsAttachments

Optic nerves: to eyes

Optic tracts: to brain

Optic chiasm: cross

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CRANIAL NERVES12 pairs

Connect to brain:CN I cerebrumCN II thalamus

CN III-XII brain stem

O O O T T A F V G V A H S S M M B M B S B B M M

Nerve names:Nerve names:

Nerve functions:Nerve functions:

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Brain Overload!!

• Oh, Once One Takes The Anatomy Final, Very Good Vacations Are Heavenly…

Or– Oh, Oh, Oh, To Touch And Feel Very Good

VIOLINS, AH!

• Some Say Marry Money, But My Brother Says Big BROWNIES Matter Most

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CN I: OLFACTORY

• SENSORY

• Smell

• From olfactory epithelium

• Olfactory nerve-bulb-tract

• (Cribriform foramina of ethmoid)

14-21

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CN II: OPTIC

• SENSORY

• From retina

• Optic nerve-chiasm-tract

• (Optic canal-sphenoid)

14-22

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CN III: OCULOMOTOR• Mostly MOTOR

• To eye muscles

• (superior orbital fissures-sphenoid)

14-22

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CN IV: TROCHLEAR• Mostly MOTOR

• To superior oblique eye muscles

• (superior orbital fissures-sphenoid)

14-22

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CN V: TRIGEMINAL• Mixed (sensory and motor)

• Ophthalmic Branch– Sensory-orbital, upper face structures

• Maxillary Branch– Sensory-lower face structures

• Mandibular Branch– Mixed-mouth

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14-24

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CN VI: ABDUCENS

14-23

• Mostly motor

• To lateral rectus eye muscles

• (superior orbital fissure)

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CN VII: FACIAL

14-25

• Mixed

• To parts of face

• Expressions, tear/salivary glands

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CN VIII: VESTIBULOCOCHLEAR

14-26

• Sensory, from inner ear

• Vestibular branch

– Balance, equilibrium

• Cochlear branch

– Hearing

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CN IX: GLOSSOPHARYNGEAL

14-27

• Mixed to head and neck

• Sensory: posterior tongue

• Motor: pharyngeal muscles (swallowing), salivary gland

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CN X: VAGUS• Mixed to visceral

organs, larynx, pharynx

• Sensory: ear, diaphragm, organs

• Motor: pharynx, digestive, respiratory, cardiovascular systems

14-28

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CN XI: ACCESSORY• Mostly motor• To muscles of neck, upper

back• Cranial root

– Fibers originate in medulla

• Spinal root– Some motor fibers

originate in spinal cord

• Join at foramen magnum

14-29

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CN XII: HYPOGLOSSAL• Mostly motor

• To tongue muscles

14-29

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• Sheep Brain Dissection!– Gloves, Scalpel, forceps (tweezers), scissors– We have goggles for you

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Figure 17-11a-b Intact sheep brain.

Olfactorybulb

Opticnerve (II)

Infundibulum

Mammillarybody

Cerebralpeduncle

Pons

Trigeminalnerve (V)

Abducensnerve (VI)

Medullaoblongata

Olfactory bulb

Olfactory tract

Infundibulum(stalk of pituitary gland)

Mammillary body

Cerebral peduncle

Trigeminal nerve (V)

Pons

Cerebellum

Glossopharyngealnerve (IX)

Vagus nerve (X)

Spinal root of theaccessory nerve (XI)

Medulla oblongata

Hypoglossal nerve (XII)

Vestibulocochlearnerve (VIII)

Facial nerve (VII)

Abducens nerve (VI)

Trochlear nerve (IV)

Oculomotor nerve (III)

Optic tract

Optic chiasma

Optic nerve (II)

Cerebrum

Ventral

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Figure 17-11c-d Intact sheep brain.

Dorsal

Cerebrum

Cerebellum

Spinal cord

Medulla oblongata

Cerebellum

Cerebrum

Olfactorybulb

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Figure 17-11a Intact sheep brain.

Olfactorybulb

Opticnerve (II)

Infundibulum

Mammillarybody

Cerebralpeduncle

Pons

Trigeminalnerve (V)

Abducensnerve (VI)

Medullaoblongata

Ventral

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Figure 17-11b Intact sheep brain.

Olfactory bulb

Olfactory tract

Infundibulum(stalk of pituitary gland)

Mammillary body

Cerebral peduncle

Trigeminal nerve (V)

Pons

Cerebellum

Glossopharyngealnerve (IX)

Vagus nerve (X)

Spinal root of theaccessory nerve (XI)

Medulla oblongata

Hypoglossal nerve (XII)

Vestibulocochlearnerve (VIII)

Facial nerve (VII)

Abducens nerve (VI)

Trochlear nerve (IV)

Oculomotor nerve (III)

Optic tract

Optic chiasma

Optic nerve (II)

Cerebrum

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Figure 17-11c Intact sheep brain.

Olfactory bulb

Cerebrum

Cerebellum

Medulla oblongata

Spinal cord

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Figure 17-11d Intact sheep brain.

Dorsal

Cerebrum

Cerebellum

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Figure 17-12 Means of exposing the dorsal midbrain structures of the sheep brain.

Occipitallobe ofcerebralhemisphered

Pineal gland

Superiorcolliculi ofcorporaquadrigemina

Inferiorcolliculi ofcorporaquadrigemina

Cerebellum

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Figure 17-13 Photograph of sagittal section of the sheep brain showing internal structures.

Cerebralhemisphere

Corpus callosum

Frontal lobe ofcerebrum

Fornix

Interthalamicadhesion(intermediate massof thalamus)

Cerebral peduncle

Optic chiasma

Parietal lobe

Cerebellum

Pineal gland

Arbor vitae

Corporaquadrigemina

Fourth ventricle

Medullaoblongata

Pons

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Figure 17-14 Coronal section of a sheep brain.

Fornix

Caudatenucleus

Thirdventricle Hypothalamus

Thalamic nuclei

Interthalamicadhesion(intermediatemass of thalamus)

Lateral ventricle

Third ventricle

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Table 17-1 The Cranial Nerves (see Figure 17.9) (1 of 4)

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Table 17-1 The Cranial Nerves (see Figure 17.9) (2 of 4)

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Table 17-1 The Cranial Nerves (see Figure 17.9) (3 of 4)

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Table 17-1 The Cranial Nerves (see Figure 17.9) (4 of 4)

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Review Figure 17-1

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Review Figure 17-2

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Review Figure 17-3

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Review Figure 17-4

Sheep Brain Dissection

• Safety First!– Sharps: blades and blade holders– Goggles– Gloves– Biohazard waste disposal

• No tissue down the drain!• Gloves also

– Cleaning the dissection trays & your instruments

Sheep Brain Dissection

• http://www.gwc.maricopa.edu/class/bio201/brain/brshpx.htm

Sheep BrainSheep Brain• Dura mater, pia mater

• Lobes (frontal, parietal, temporal, occipital) Superficial

• Pituitary gland

• Olfactory bulbs

• Optic nerves, optic chiasm, optic tract

• Oculomotor nerve

Superficial

Sheep BrainSheep Brain• Cerebral cortex (gray matter)

• Cerebral white matter

• Corpus callosum

• 4th ventricle

• Thalamus

• Hypothalamus

• Pineal gland

• Superior colliculi

• Inferior colliculi

• Pons

• Medulla oblongata

• Cerebellum (arbor vitae, cerebellar cortex)

Longitudinal section

Sheep BrainSheep Brain• Lateral ventricles Transverse section

Sheep BrainSheep Brain• Dura mater, pia mater• Pituitary gland• Olfactory bulbs• Optic nerves, optic chiasm, optic tract• Oculomotor nerve• Cerebral cortex (gray matter)• Cerebral white matter• Corpus callosum• Lateral, third, 4th ventricles• Thalamus• Hypothalamus• Pineal gland• Superior colliculi• Inferior colliculi• Pons• Medulla oblongata• Cerebellum (arbor vitae, cerebellar cortex)

Superficial

Longitudinal section & Transverse section

Figure 17-6a Cerebellum.

Anteriorlobe

Primaryfissure

Posteriorlobe

Horizontalfissure

Vermis

Figure 17-6b Cerebellum.

Brain stem(midbrain)

Cerebellarcortex

Arborvitae

Deepcerebellarnuclei

Caudal(inferior)

Vermis(cut)

Figure 17-7a Meninges of the brain.

Skin of scalp

Periosteum

Bone of skull

Periosteal

MeningealDura mater

Arachnoid mater

Pia mater

Arachnoid villus

Blood vessel

Falx cerebri(in longitudinalfissure only)

Subarachnoidspace

Subduralspace

Superior sagittalsinus

Figure 17-7b Meninges of the brain.

Straightsinus

Crista galli ofthe ethmoidbone

Pituitarygland

Falx cerebelli

Tentoriumcerebelli

Falx cerebri

Superiorsagittal sinus

Figure 17-7c Meninges of the brain.

Arachnoid materover medullaoblongata

Cerebellum

Falx cerebelli

Tentoriumcerebelli

Occipital lobe

Falx cerebri

Superiorsagittal sinus

Parietalbone

Transversesinus

Scalp

Dura mater

Temporalbone

Figure 17-8a Location and circulatory pattern of cerebrospinal fluid.

Lateral ventricle

Anterior horn

Interventricularforamen

Third ventricle

Cerebral aqueduct

Fourth ventricle

Central canal

Septumpellucidum

Inferiorhorn

Lateralaperture

Anterior view

Figure 17-8b Location and circulatory pattern of cerebrospinal fluid.

Lateral ventricle

Anterior horn

Interventricularforamen

Third ventricle

Cerebral aqueduct

Fourth ventricle

Central canal

Lateralaperture

Medianaperture

Posteriorhorn

Inferiorhorn

Left lateral view

Figure 17-8c Location and circulatory pattern of cerebrospinal fluid.

Arachnoid villus

Subarachnoid space

Arachnoid mater

Meningeal dura mater

Periosteal dura mater

Right lateral ventricle(deep to cut)

Tentorium cerebelli

Choroid plexusof fourth ventricle

Inferior end ofspinal cord

Central canalof spinal cord

Spinal dura mater

Median aperture

Fourth ventricle

Lateral aperture

Cerebral aqueduct

Third ventricle

Interventricularforamen

Choroid plexus

Superiorsagittal sinus

Figure 17-9 Ventral aspect of the human brain, showing the cranial nerves.

Frontal lobe

Temporal lobe

Infundibulum

Facialnerve (VII)

Vestibulo-cochlearnerve (VIII)

Glossopharyngealnerve (IX)

Vagus nerve (X)

Accessory nerve (XI)

Hypoglossal nerve (XII)Medulla oblongata

Abducensnerve (VI)

Cerebellum

Trigeminalnerve (V)

Trochlearnerve (IV)

Oculomotornerve (III)

Optic tract

Optic chiasma

Olfactory tract

Optic nerve (II)

Olfactory bulb

Filaments ofolfactory nerve (I)

Figure 17-10 Photograph of lateral aspect of the human brain.

Left cerebralhemisphere

Brain stem

Cerebellum

Transversecerebralfissure