Cranial Nerves 1 Lectureff

8/4/2019 Cranial Nerves 1 Lectureff

http://slidepdf.com/reader/full/cranial-nerves-1-lectureff 1/38

CRANIAL NERVES I.

OUTLINE

I. HISTORY OF ANATOMY

II. CLASSIFICATION OF

TYPES OF NEURONS INCRANIAL NERVES



SKELETON FROM PERSIANMANUSCRIPT IN 1300;

PRIOR TO DISSECTIONSEE HUMAN ANATOMYIN WARS



PREGNANT WOMANGERMANY ABOUT 1400LATE MIDDLE AGES

DISSECT ONLYCRIMINALSFEW FEMALES;EMBRYO THOUGHT OF

AS LITTLE PERSON



AROUND

1400-1500ANATOMYTAUGHT INUNIVERSITIES

WITHDISSECTION



VESALIUS(1514-1564)

ANATOMISTS

BECAMEARTISTS



ANDREASVESALIUS1543UNIVERSITYOF PADUA

DELTOID

BRACHIO-RADIALIS



LEONARDODA VINCI

1452-1518

ARTISTSBECAME

ANATOMISTS



DRAWINGSOFFETUSINSITU



STUDYANATOMYTO MOREACCURATELY

REPRESENTHUMANBODYIN

ART

DA VINCI DRAWING OF SKULL



http://www.nlm.nih.gov/

History of Medicine Division



BARTOLOMEO EUSTACHIO 1510?-1574

- AUDITORY TUBE =EUSTACHIAN TUBE- DISSECT BODY IN FEW DAYS- DRAWING IS MADEFROM MEMORY OF

MANY DISSECTIONS



ENLARGEMENTOF BRACHIALPLEXUS

M



ENLARGEMENTOF BRAIN

OPTIC CHIASMV1, V2, V3



A. contain inflow/outflow of brain;spinal nerves contain inflow/outflowof spinal cord.

B. contain types of similar to thosefound in spinal nerves; ex. sensoryaxons to skin.C. contain types of neurons not foundin spinal nerves; ex. taste fibers.

D. Many cranial nerves contain morethan one type of neuron.E. To analyze types of neurons indifferent cranial nerves, system of

classification based upon anatomy,embryology and homologies; TYPESOF NEURONS are calledFUNCTIONAL COMPONENTS

CRANIAL NERVES

CRANIALNERVES

SPINAL

NERVES



II. BASIS OF CLASSIFICATION - three letter system.

A. First letterG = General = types of neurons found both in

spinal nerves and cranial nerves.

S = Special = types of neurons only found incranial nerves not spinal nerves.

B. Second letterS = Somatic = types of neurons innervating

structures derived from somites.V = Visceral = types of neurons innervating gut,

structures derived from or associated with gut and branchialarches; also vascular system, smooth muscle, internal organs andglands.

C. Third letterA = Afferent = sensory neurons.E = Efferent = motor neurons to skeletal and

smooth muscle; also secretomotor neurons to glands.



III. CLASSIFICATION OF INNERVATION AS

FUNCTIONAL COMPONENTSA. General Innervation - like spinal cord

1. GSE (General Somatic Efferent) - motor to somatic

voluntary skeletal muscles (derived from somites).2. GSA (General Somatic Afferent) - sensory to skin,

joints, muscle and tendon receptor endings, nasal and oral cavity.3. GVE (General Visceral Efferent) = Autonomic

Efferents - motor to smooth muscles in general and smooth muscles of

skin (arrector pilae muscles) and blood vessels, secretomotor to glands.4. GVA (General Visceral Afferent) - sensory to gut

and its derivatives, pharynx, blood vessels, glands and internal organs.

B. Special Innervation - only found in head.

1. SSA (Special Somatic Afferent) - special sensesof vision, auditory sensation and vestibular apparatus.

2. SVA (Special Visceral Afferents) - chemical

senses of taste and by analogy smell.3. SVE (Special Visceral Efferents) - motor to

voluntary skeletal muscles derived from branchial arches (these muscles

develop in association with pharynx, which is rostral end of gut andtherefore visceral).



I. OlfactoryII. Optic

III. OculomotorIV. TrochlearV. TrigeminalVI. Abducens

VII. FacialVIII. Vestibulo-cochlearIX. Glossopharyngeal

X. VagusXI. AccessoryXII. Hypoglossal

CRANIAL NERVES





GSE - General Somatic Efferents

motor to skeletal muscle derived fromsomites; only two groups in head

6 weeks 8 weeks

OccipitalPreotic 1) Preotic myotomes

(somitomeres) formextrinsic musclesof eye:

III - Oculomotor,IV - Trochlear,VI - Abducens.

2) Occipital myotomesform muscles of tongue- XII

Hypoglossal N.



GSA - General Somatic Afferents

sensory to skin, ORAL cavity, NASAL cavity, joints, muscles

ALMOST ALLTRIGEMINAL VEXCEPTION:SKIN OF OUTER EAR

ALSO1) VII- FACIAL2) IX - GLOSSO-PHARYNGEAL3) X - VAGUS

BELL'S PALSY (VII) - PARALYSIS OF FACIAL MUSCLES; INRECOVERY, PATIENTS COMPLAIN OF EARACHES



SENSORY CELL BODIES IN DORSAL ROOT GANGLIA

IN SPINAL CORD

DORSAL

ROOTGANGLION



SENSORY GANGLIA ARE ATTACHED TO CRANIAL NERVES

- cell bodies ofsensory neurons

in Trigeminal Nerveare inTrigeminal(Semilunar)Ganglion

Cell bodies of sensory neurons in VII (Facial Nerve) in

Geniculate Ganglion



GVE - General Visceral Efferents

SYMPATHETIC - thoraco-lumbarPARASYMPATHETICS - cranio-sacral - ganglia close to

target organ



SYMPATHETICS IN THORAX, ABDOMEN

Thoraco-

LumbarT1-T12,L1, L2



SYMPATHETICS TO HEAD

- First neuronOut T1, T2

AscendsChain



SYMPATHETICS TO HEAD

Second neuron In

SuperiorCervical Ganglia

Joins Plexus on

Internal and ExternalCarotid Arteries1) Unnamed branches2) Few named branches

Ex. Deep Petrosal N.



PARASYMPATHETICS - IN CRANIAL NERVES

+palate

III

VII

IX

X



GVA - General Visceral Afferents

NasalCavityGSA

OralCavityGSA

Sensory to Pharynx and derivatives

All Pharynx is GVA

In 3 Cranial Nerves

NASOPHARYNX - VII

OROPHARYNX - IX

LARYNGOPHARYNX - X



SSA - Special Somatic Afferents

Special senses only found in head - SSA =vision II, hearing and balance VIII

II-OPTIC

NERVE

fiberscross at

opticchiasm



SSA - Special Somatic Afferents

VIII -VESTIBULO-

COCHLEAR

to 1) cochlea - hearing2) semicircular canals -

balance

in petrous part oftemporal bone

VIII



SVA - Special Visceral Afferents

Chemical senses - Taste and Smell

I - OLFACTORY NERVE



SVA - Special Visceral Afferents

Chemical Sense - TASTE - in three cranial nerves

X - VAGUS -ant. to epiglottis

IX - GLOSSO-

PHARYNGEALpost. 1/3 of tongue

VII - FACIAL -

ant. 2/3 of tongue

TONGUE



SVE - Special Visceral Efferents

- motor to voluntary skeletal muscles derived frombranchial arches- visceral because develop in pharynx then migrate

Second -Facial

VII

ThirdGlosso-pharyngeal

IX

First -TrigeminalV

FourthVagusX

SixthAccessoryXI





III. CLASSIFICATION OF INNERVATION ASFUNCTIONAL COMPONENTS

A. General Innervation - like spinal cord1. GSE (General Somatic Efferent) - motor to somatic

voluntary skeletal muscles (derived from somites).2. GSA (General Somatic Afferent) - sensory to skin,

joints, muscle and tendon receptor endings, nasal and oral cavity.3. GVE (General Visceral Efferent) = Autonomic

Efferents - motor to smooth muscles in general and smooth muscles of

skin (arrector pilae muscles) and blood vessels, secretomotor to glands.4. GVA (General Visceral Afferent) - sensory to gut

and its derivatives, pharynx, blood vessels, glands and internal organs.

B. Special Innervation - only found in head.

1. SSA (Special Somatic Afferent) - special sensesof vision, auditory sensation and vestibular apparatus.

2. SVA (Special Visceral Afferents) - chemicalsenses of taste and by analogy smell.

3. SVE (Special Visceral Efferents) - motor tovoluntary skeletal muscles derived from branchial arches (these muscles

develop in association with pharynx, which is rostral end of gut and

therefore visceral).







Before you Leave – Make Incision

Around Head, Above Ears

Peel MusclesFrom Skull On

Back Of NeckExpose Joint

Occip-C1

Cranial Nerves 1 Lectureff

Documents