介绍第10 11章咽弓鳃infish

NeuroanatomyNeuroanatomyXiangya

2nd

HospitalZhang

HeRunner

up

in

Anatomical

Society

Best

Image

Award2013.

Axial

diffusion-weighted

MRI

tractographyimage

of

living

human

brain.Afferent

nucleiGeneral

sensory

information

(touch,

pressure,pain,

temperature)

from

head

to

pons

andterminate

in

trigeminal

sensory

nucleus

(largenucleus

run

whole

brainstem

and

cervical

cord).Special

sense

of

motion/position

andhearingterminate

in

vestibular

and

cochlear

nuclei

inmedulla.Visceral

afferent,

including

taste,

terminate

innucleus

solitarius

of

medulla.Efferent

nucleiOn

basis

of

embryological

derivation,

efferentcranial

nerve

nuclei

divided

into

three

groups

indiscontinuous

longitudinal

column.Nuclei

of

the

somatic

efferent

cellcolumnOculomotor

nucleus

to

IIITrochlear

nucleus

to

IVAbducens

nucleus

to

VIHypoglossal

nucleus

to

XIINuclei

of

the

branchiomotor

cell

columnInnervate

striated

muscle

derived

frompharyngeal

arch(咽弓)in

human

and

branchialarch(鳃弓)infish.(also

special

visceral

efferent)Trigeminal

motor

nucleus

to

VFacial

motor

nucleus

to

VIINucleus

ambiguus

to

IX,

Xcranial

part

of

XINuclei

of

parasympathetic

cell

columnEdinger–Westphalnucleus

to

IIISuperior

salivatory

nuclei

to

VIIInferior

salivatorynuclei

to

IXDorsal

motor

nucleus

of

vagus

to

X(in

vagus

distributed

to

thoracic

and

abdominal

viscera)III:

Oculomotor

nerveInclude:General

somatic

efferentGeneral

visceral

efferentOcularmotor

nucleus

supply

levator

palpebrae

superioris

andsuperior

rectus

(Superior

branch),

medial

rectus,

inferior

rectus,and

inferior

oblique

muscles

(Inferior

branch).EW

nucleus

supply

parasympathetic

fiber

to

eye

via

ciliaryganglion

to

control

sphincter

pupillae

muscle

(affecting

pupilconstriction)

and

ciliary

muscle

(affecting

accommodation).Pupillary

light

reflex

Pretectal

nucleus

project

crossed

and

uncrossed

fibers

toipsilateral

and

contralateral

EW

nuclei.Accommodation

reflex

Nearby

object,

visual

cortex,

corticobulbar,

optic

axis

convergent,EW

nuclei,

iris

constriction.Short

ciliary

nerveDirect

light

reflexConsensual

light

reflexPretectalnucleusPathways

in

Ciliary

ganglionParasympathetic,

Sympathetic,

Sensory

nervesClinical

significanceParalysis

of

oculomotor

nerve

due

to:Direct

traumaDemyelinating

disease

(e.g.,

multiple

sclerosis)Increased

intracranial

pressure

(leading

to

uncal

herniation)due

to

a

space-occupying

lesion

(brain

cancer)

or

SAH

(aneurysm)Microvascular

disease

(diabetes)In

diabetes

or

older,

oculomotor

palsy

with

sparing

ofpupillary

reflex

due

to

fiber

controlling

pupilsuperficial

and

spared

from

ischemia

of

diabetes.Conversely,

aneurysm

compress

oculomotor

nerveaffect

superficial

fiber

manifest

as

III

nerve

palsy

withloss

of

pupillary

reflex.IV:

Trochlear

nerveUnique

among:Smallest

nerve

containing

axon.Greatest

intracranial

length.Only

cranial

nerve

exit

from

dorsal.Lesion

of

nucleusaffect

contralateral

eye

while

allothernuclei

ipsilateral.Innervating

muscle

on

opposite

side.Clinical

significanceExamination:Look

'down

and

in'

for

exam

superior

oblique,

Alsoask

reading

newspaper

or

walking

down

stairs.(Vertical

diplopia

and

Torsional

diplopia)Causes:Peripheral

lesion:

acute

palsy

is

head

trauma

stretchor

compress.

Chronic

palsy

is

congenital

IV

nerve

palsywhen

compensation

fail.Central

lesion:

is

to

nucleus.

Cortical

control

of

eye movement

(saccades,

smooth

pursuit)

is

conjugate gaze,

not

unilateral

eye

movement.VI:

Abducens

nerveCauses:Peripheral

lesion:

compress

or

damage;

most

common

isdiabetic

neuropathy;

Rare

cause

are

Wernicke

and

Tolosa

Hunt.“False

localizing

sign”:

right-sided

nerve

palsy

does

notnecessarily

imply

a

right-sided

cause.Nuclear

lesion:Dorsal

pons:

VI+VII;Ventral

pons:

VI+corticospinal;Nucleus

has

two

cells:motor

neuron

to

lateral

rectus

muscle,Interneuron

by

medial

longitudinal

fasciculusSupranuclear

lesion:

bilateralClinical

significanceLesion

of

cranial

nerve

III,

IV,VIV:

Trigeminal

nerve

(Largest

cranial

nerve)Sensory

nerve

for

head,

Motor

for

mastication.Trigeminal

nucleus

receive

differenttype

of

sensory

information:Spinal

trigeminal

nucleus

receivepain-temperature

fibers;Principal

sensory

nucleus

receivetouch-position

fiber;Mesencephalic

nucleus

receiveproprioceptor

andmechanoreceptor

fiber

from

jawand

teeth.Spinal

trigeminal

nucleusRepresent

pain-temperature

sensation

from

face.

Pain-temperature

fiber

from

peripheral

nociceptor

carriedin

V,VII,

IX,

X.Somatotopic

representationWithin

spinal

trigeminal

nucleus,

information

isrepresented

in

an

onion-skin

fashion.Spinal

trigeminal

nucleus

send

pain-temperature

tothalamus,

mesencephalon,

reticular

formation.The

latter

pathway

is

analogous

to

spinomesencephalicand

spinoreticular

tract.

Mesencephalon

modulate

painfulinput

before

reach

level

of

conscious.

Reticular

formationresponsible

automatic

(unconscious)

orientation

of

body

topainful

stimuli.Principal

nucleusRepresent

touch-position

from

face

and

mouthvia

V,

VII,

IX,

X.Analogous

to

dorsal

column

nuclei(gracile

and

cuneate

nuclei)

of

spinal

cord.Touch-position

from

teeth

and

jaws

of

onesiderepresent

bilaterally

to

thalamus

and

cortex.Position,

refer

to

conscious

proprioception.Proprioceptor

(muscle

spindle

and

Golgi

tendon

organ)for

joint

position

and

muscle

movement.Unconscious

level

(by

cerebellum

and

vestibular

nuclei)Mesencephalic

nucleusNot

a

true

nucleus

but

sensory

ganglion

(liketrigeminal

ganglion)

embed

in

brainstem.

This"internal

ganglion"

cells

discovered

by

medicalstudent

Sigmund

Freud.Two

type

of

sensory

cells:Proprioceptor

from

jaw;

Mechanoreceptor

from

teeth.Automatic

biting,

chewing,

swallowing

requirelittle

conscious

and

involve

sensory

component(touch-position

feedback)

process

at

unconscious

levelin

mesencephalic

nucleus.Touch-position

from

body

sent

to

ventralposterolateral

nucleus

(VPL)

of

thalamus

andface

to

ventral

posteromedial

nucleus

(VPM).Then

project

to

parietal

lobe

somatotopically

as"little

man".Pain-temperature

sent

to

VPL

(body)

and

VPM(face).

Also

to

other

thalamic

nuclei

and

projectto

insular

and

cingulate

for

simultaneousperception

(sight,

smell,

taste,

hearing

andbalance)

in

memory

and

emotional

state.From

Muscle

of

masticationTemporomandibular

jointRelayedfrom

face,

scalp,cornea,nasal

oralcavity,

teeth,

paranasalsinus,

intracranial

dura

and

arteryTo

substantia

gelatinosain

cord,

considered

to

bebrainstem

homologueTrigeminal

lemniscusTrigeminalmotor

nucleusTo

masticate

(masseter

andtemporalis

to

close

jaw,lateralandmedialpterygoid翼to

open

jaw)Also

innervate

tensortympani(鼓膜张肌)within

middle

earAnalogous

to

spinaldorsalroot

gangliaSubstantia

gelatinosa（脊髓胶状质）in

lamina

I–III,receive

smallest

myelinated

(A

delta)andunmyelinated

(C)nociception

afferent

withglutamic

acid

and

substance

P

as

transmitter

toascending

spinothalamic,

spinoreticular

tract.眼轮匝肌V

from

nasal

mucosaX

from

larynx

and

tracheaVII:

Facial

nerveFacial

nerve

contain

motor(medial

root)

,sensory

and

parasympathetic

(lateral

root).Sensory:

geniculate

ganglionfor

taste

to

nucleussolitarius

of

medulla

project

to

thalamus

and

parietallobe.Motor:

facial

motor

nucleus

of

pons

looping

overabducens

nucleus

to

muscle

of

facial

expression.Parasympathetic:

superior

salivatory

nucleus

of

ponssubmandibular

and

pterygopalatine

ganglia.Facial

motor

nucleus

receive

afferentsfrom:Cerebral

cortex:

to

upper

face

musclebilateral

and

lower

face

unilateral.Reflex

connection:to

protective

eye

closurein

response

to

visual

stimuli(superiorcolliculus),

tactile

corneal

reflex

(trigeminalsensory

nucleus), stapedius

muscle镫骨肌

contact

to

loud

noise

(superior

olivarynucleus).翼腭神经节镫骨肌鼓索茎乳孔VIII:VestibulocochlearnerveSensorynerveconveyimpulse

from

inner

earVestibular

nerve

forposition

and

movementofhead;Cochlear

nerve

forauditory

information.Vestibular

nerveVestibular

nerve

make

dendritic

contact

withhair

cell

of

vestibular

portion

of

membranouslabyrinth;Vestibular

ganglion

in

internal

auditory

meatus;Vestibular

system

locate

in

inner

ear

withbipolar

ganglion

extend

to

five

sensory

organs.End

in

four

vestibular

nuclei

(superior,

inferior,medial

and

lateral

vestibular

nuclei)

in

medulla.Vestibular

nerve

transmit

sensory

information

byhair

cell

locate

in

two

otolith

organ耳石(utricle椭圆囊

and

saccule球囊)and

three

semicircular

canal

viavestibular

ganglion.Otolith

organ

reflect

gravity

and

linearacceleration

of

head.Semicircular

canal

reflect

rotational

movementofhead.Both

necessary

for

sensation

of

bodypositionand

gaze

stability

to

moving

environment.Vestibular

nuclei

to

other

regions:To

vestibulospinal

tract

for

body

posture.To

vestibulocerebellum

(flocculonodular

lobe)for

equilibrium.To

abducens,

trochlear

and

oculomotor

forcoordination

of

head

and

eye

movement

viamedial

longitudinal

fasciculus.To

thalamus

and

cortex

for

consciousawareness

of

vestibular

sensation.Vestibulo-ocular

reflexRotation

of

head

triggerinhibitory

signal

toextraocular

muscle

onone

side

and

excitatorysignal

to

the

other.Result

is

compensatorymovement

of

eye.CochlearnerveHair

cell

of

organ

of

Corti

activate

receptor

inresponse

to

pressure

wave

via

transduction

ofsound

to

spiral

ganglia

of

innerear.Nerve

bifurcate

and

end

in

dorsal

and

ventralcochlear

nuclei,thenascending

auditorypathway

to

thalamus

and

Wernicke

area.Unilateral

lesion

of

auditory

pathway

do

notcause

monaural

deafness,

but

manifest

as

lossofauditoryacuityand

inability

tolocalizedirectional

origin

of

sound.Descending

auditory

pathway:Olivocochlear

fibre

(橄榄耳蜗系统)leave

from

superiorolivary

nucleus

in

vestibulocochlear

nerve

and

end

inorgan

of

Corti.Medial

olivocochlear

system

(MOCS)

is

prior

tolateral

olivocochlear

system

(LOCS)

for

itsmyelinatedfibre

easier

to

electrically

stimulate

and

record.Hypothesis

of

MOCS

in

three

category:Protect

cochlear

against

loud

sound;Development

of

cochlea

function;Detection

and

discrimination

of

sound

in

noise.Organ

of

Cortior

spiral

organHigh-frequencyIntermediate

frequencyLow-frequencyHidden

withinlateral

fissureWernicke

areaAuditory

information

contextualinterpretIX:

GlossopharyngealnervePrincipally

sensory;Also

parasympathetic;A

few

motor.Sensory:Sensation

in

pharynx,

posterior

third

oftongue, Eustachian

tube

and

middle

earTaste

of

pharynx,

posterior

third

of

tongueChemoreceptor

in

carotid

body

andbaroreceptor

in

carotid

sinus.motor

:nucleus

ambiguus

tostylopharyngeusfor

swallowing

(茎突咽肌辅助喉头上升).Parasympathetic:inferior

salivatory

nucleusto

otic

ganglion耳then

parotid

salivary

gland唾液腺.呕吐X:

Vagus

nerveAfferent,

Motor:Parasympathetic:From

dorsal

motor

nucleus

ofvagus,

To

cardiovascular,respiratory,

gastrointestinal.Also

sympathetic

role

byactivation

of

chemoreceptordue

to

hypoxemia

enablevasoconstriction

and

increaseblood

pressure.Afferent

fibre

of

vagus:General

sensation

from

pharynx,

larynx,oesophagus,

tympanic

membrane,

external

auditorymeatus

to

trigeminal

sensory

nucleus;Chemoreceptor

in

aortic

body,

baroreceptor

inaortic

arch,

receptor

throughout

thoracic

abdominalviscera

end

in

nucleus

solitarius.Motor

fibre

of

vagus:From

nucleus

ambiguus

to

softpalate,

pharynx,larynx,

upper

oesophagus

to

control

of

speech

andswallowing.XI:

Accessory

nervePurely

motor,

innervated

by

bilateral

cortex.Cranial

root

of

accessory

nerve

origin

fromnucleus

ambiguus.

At

jugular

foramen

joinvagus

nerve

to

soft

palate,

pharynx,

larynx.Spinal

root

arise

from

C1-C5

spinal

greymatter.

Not

via

ventral

root

but

enter

cranialcavity

through

foramen

magnum.

Then

joinwith

cranial

root

leave

cranial

cavity

throughjugular

foramen.Moveheadand

shoulderXII:

Hypoglossal

nervePure

motor

in

function.Hypoglossal

nucleus

to

extrinsic

andintrinsicmuscle

of

tongue

to

move

and

change

shape.From

reticular

formation,

involuntary

andunconscious

movement

of

speech,

articulation,swallowing

to

clear

mouth

of

saliva.Innervation

of

hypoglossal

nucleus

from

motorcortex

is

bilateral,但主管伸舌作用的颏舌肌由对侧大脑皮质支配.From

nucleus

solitarius

and

trigeminalsensory

nucleus

for

reflex

of

chewing,sucking

and

swallowing.Also

from

corticobulbar

fibre

to

voluntarymovement

of

tongue

in

speech.Signal

from

muscle

spindleon

the

tonguetravel

through

hypoglossal

nerve,

movingonto

lingual

nerve

which

synapse

ontrigeminal

mesencephalic

nucleus.Control

equilibrium,

posture,

muscle

tone,coordination

at

an

unconscious

level.Connect

medulla,

ponsandmidbrainbyinferior,middle

and

superior

peduncle.Consist

medial

vermis

and

lateral

hemisphere.Divided

anterior,

posterior,

flocculonodularlobes.Primary

fissure

divide

small

anterior

lobe

and

larger

posterior

lobe.Posterolateral

fissure

demarcate

flocculus

(hemisphere)

and

nodule(vermis),

together

form

flocculonodular

lobe.Cerebellar

cortexAfferent

to

cerebellum

from

(extracerebellar):Spinal

cord

(spinocerebellar

fibre),Inferior

olivary

nucleus

(olivocerebellar

fibre),Vestibular

nuclei

(vestibulocerebellar

fibre)

,Pons(pontocerebellarfibre)Also

afferent

from

(intracerebellar):Purkinjecell

(of

cerebellar

cortex)Efferent

from

cerebellum

to:Reticular,

vestibularnuclei

(of

medulla,

pons),Red

nucleus

(ofmidbrain),Thalamus

ventral

lateral

nucleus.Origin

of

cerebellarefferent

fibre顶核Based

upon

phylogenetic,

anatomical

and

functional:Archicerebellum