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 PARIETAL ON PARIETAL LOBE LOBE Primary Primary

somatosensory somatosensory areaarea

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

DIENCEPHALON= thalamus + DIENCEPHALON= thalamus + hypothalamushypothalamus

Sensory Nerve Sensory Nerve AttachmentsAttachments

Optic nerves: to eyes

Optic tracts: to brain

Optic chiasm: cross

Pineal Gland

Endocrine Endocrine AttachmentsAttachments

MIDBRAINMIDBRAIN

CORPORA CORPORA QUADRIGEMINAQUADRIGEMINA

HINDBRAINHINDBRAIN

HINDBRAIN--HINDBRAIN--cerebellumcerebellum

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

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

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:

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 Dissections

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

• http://www.biology.ualberta.ca/courses.hp/zoo.225/lab8.html

• http://darwin.baruch.cuny.edu/gelfond/Bio1005/neural.htm

• http://a-s.clayton.edu/biology/biol1151L/lab10/lab_10.htm