exercise 19: brain and cranial nerves

EXERCISE 19: EXERCISE 19:

BRAIN AND CRANIAL BRAIN AND CRANIAL NERVESNERVES

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

FOREBRAINFOREBRAIN

MIDBRAINMIDBRAIN

HINDBRAINHINDBRAIN

CEREBRUM

Transverse Fissure

ON FRONTAL LOBE ON FRONTAL LOBE Primary motor areaPrimary motor area

ON ON PARIETAL PARIETAL

LOBE LOBE Primary Primary somato-somato-sensory sensory

areaarea

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

DIENCEPHALON= thalamus + DIENCEPHALON= thalamus + hypothalamushypothalamus

Pineal Gland

Endocrine Endocrine AttachmentsAttachments

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

• Mesencephalic or CEREBRAL aqueduct

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

MIDBRAINMIDBRAIN

CORPORA CORPORA QUADRIGEMINAQUADRIGEMINA

HINDBRAINHINDBRAIN

HINDBRAIN--HINDBRAIN--cerebellumcerebellum

Don’t Forget!

• Sheep Brain Dissection next class!

Sensory Nerve Sensory Nerve AttachmentsAttachments

Optic nerves: to eyes

Optic tracts: to brain

Optic chiasm: cross

CRANIAL NERVES12 pairs

Connect to brain:CN I cerebrumCN II thalamusCN 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:

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

CN I: OLFACTORY

• SENSORY• Smell• From olfactory

epithelium• Olfactory nerve-bulb-

tract• (Cribriform foramina of

ethmoid)14-21

CN II: OPTIC

• SENSORY

• From retina

• Optic nerve-chiasm-tract

• (Optic canal-sphenoid)

14-22

CN III: OCULOMOTOR

• Mostly MOTOR

• To eye muscles

• (superior orbital fissures-sphenoid)

14-22

CN IV: TROCHLEAR• Mostly MOTOR

• To superior oblique eye muscles

• (superior orbital fissures-sphenoid)

14-22

CN V: TRIGEMINAL• Mixed (sensory and motor)

• Ophthalmic Branch– Sensory-orbital, upper face structures

• Maxillary Branch– Sensory-lower face structures

• Mandibular Branch– Mixed-mouth

14-24

CN VI: ABDUCENS

14-23

• Mostly motor

• To lateral rectus eye muscles

• (superior orbital fissure)

CN VII: FACIAL

14-25

• Mixed

• To parts of face

• Expressions, tear/salivary glands

CN VIII: VESTIBULOCOCHLEAR

14-26

• Sensory, from inner ear

• Vestibular branch

– Balance, equilibrium

• Cochlear branch

– Hearing

CN IX: GLOSSOPHARYNGEAL

14-27

• Mixed to head and neck

• Sensory: posterior tongue

• Motor: pharyngeal muscles (swallowing), salivary gland

CN X: VAGUS• Mixed to visceral

organs, larynx, pharynx

• Sensory: ear, diaphragm, organs

• Motor: pharynx, digestive, respiratory, cardiovascular systems

14-28

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

CN XII: HYPOGLOSSAL

• Mostly motor

• To tongue muscles

14-29

CRANIAL NERVES

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

Superficial

Sheep BrainSheep Brain• Cerebral cortex (gray matter)

• Cerebral white matter

• Corpus callosum

• third, 4th ventricles

• 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• 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