01 cranial nerve overview

CRANIAL NERVES

Overview

Cranial NervesCranial Nerves NameName

II Olfactory NerveOlfactory Nerve

IIII Optic NerveOptic Nerve

IIIIII Oculomotor NerveOculomotor Nerve

IVIV Trochlear NerveTrochlear Nerve

VV Trigeminal NerveTrigeminal Nerve

VIVI Abducens NerveAbducens Nerve

VIIVII Facial NerveFacial Nerve

VIIIVIII Vestibulocochlear NerveVestibulocochlear Nerve

IXIX Glossopharyngeal NerveGlossopharyngeal Nerve

XX Vagus NerveVagus Nerve

XIXI Accessory NerveAccessory Nerve

XIIXII Hypoglossal NerveHypoglossal Nerve

Olfactory bulb

Olfactory tract

Cranial Nerves

Olfactory (I)Optic (II)Oculomotor (III)Trochlear (IV)Trigeminal (V)Abducens (VI)Facial (VII)Vestibulocochlear (VIII)

Glossopharyngeal (IX)

Vagus (X)Accessory (XI)Hypoglossal (XII)

Pituitary glandOptic tract

Cranial Nerves Cranial Exit

I Cribriform plate

II Optic canal

III Superior orbital fissure

IV Superior orbital fissure

V V1: Superior orbital fissure

V2: Foramen rotundum

V3: Foramen ovale

VI Superior orbital fissure

VII Internal acoustic meatusStylomastoid foramen

VIII Internal acoustic meatus (does not leave)

IX Jugular foramen

X Jugular foramen

XI Jugular foramen

XII Hypoglossal canal

Exit points

Cranial Nerves ComponentsCranial Nerves Components

Cranial Nerves Components

I sensory

II sensory

III motor

IV motor

V mix

VI motor

VII mix

VIII sensory

IX mix

X mix

XI motor

XII motor

& other

& other

1818

Sensory /Afferent

General Special

Motor/ Efferent

General Special

SomaticGSA

VisceralGVA

VisceralSVA

SomaticSSA

SomaticGSE

VisceralGVE

VisceralSVE

sensationfrom skin,

mucousmembrane

visceralsensation

frominternalorgans

smell &taste

vision,balance,

& hearing

innervateskeletalmusclesnot frombranchial

arches

innervatesmoothmuscles& glands

(autonomic)

innervateskeletalmuscles

frombranchial

arches

components

2020

Sensory /Afferent

General Special

Motor/ Efferent

General Special

SomaticGSA

VisceralGVA

VisceralSVA

SomaticSSA

SomaticGSE

VisceralGVE

VisceralSVE

sensationfrom skin,

mucousmembrane

visceralsensation

frominternalorgans

smell &taste

vision,balance,

& hearing

innervateskeletalmusclesnot frombranchial

arches

innervatesmoothmuscles& glands

(autonomic)

innervateskeletalmuscles

frombranchial

arches

components

2121

Sensory /Afferent

General Special

Motor/ Efferent

General Special

SomaticGSA

VisceralGVA

VisceralSVA

SomaticSSA

SomaticGSE

VisceralGVE

VisceralSVE

sensationfrom skin,

mucousmembrane

visceralsensation

frominternalorgans

smell &taste

vision,balance,

& hearing

innervateskeletalmusclesnot frombranchial

arches

innervatesmoothmuscles& glands

(autonomic)

innervateskeletalmuscles

frombranchial

arches

components

2222

Sensory /Afferent

General Special

Motor/ Efferent

General Special

SomaticGSA

VisceralGVA

VisceralSVA

SomaticSSA

SomaticGSE

VisceralGVE

VisceralSVE

sensationfrom skin,

mucousmembrane

visceralsensation

frominternalorgans

smell &taste

vision,balance,

& hearing

innervateskeletalmusclesnot frombranchial

arches

innervatesmoothmuscles& glands

(autonomic)

innervateskeletalmuscles

frombranchial

arches

components

Cranial Nerves

Components

I SVA

II SSA

III GSE, GVE

IV GSE

V SVE, GSA

VI GSE

VII SVE, GVE, SVA, GSA, GVA[?]

VIII SSA, SSA

IX SVE, GVE, SVA, GVA, GSA

X SVE, GVE, SVA, GVA, GSA

XI [Cranial]SVE, [Spinal]GSE

XII GSE

This slide is only for reference here; however you will memorize every detail of this slide in Med 3 – Neuroscience. So it is just matter of time!

3 kind of Motor/Efferent 3 kind of Motor/Efferent fibers:fibers:

1. GSE [somatic motor]1. GSE [somatic motor]

General Somatic efferent Cell bodies of these neurons lie in brainstem or spinal

cord and their axons innervate skeletal muscles These skeletal muscles are derived from Somites. CN – 3,4,6,11[spinal],12 Also note that all the 31 spinal nerves have GSE fibers.

2. SVE [bra2. SVE [brannchial motor]chial motor] Special Visceral efferent Functionally same as GSE and supply also

skeletal muscles Difference is, these skeletal muscles are

derived from Branchial arches and not from somites

Therefore also known as Branchial Motor Component

CN – 5,7,9,10,11[cranial] Logic behind using the term visceral here is that in lower animals the

muscles derived from branchial arches are not skeletal muscles but smooth muscles.

3. GVE [visceral motor]3. GVE [visceral motor]

General Visceral Efferent These fibers innervate Smooth Muscles or

Glands of internal organs[=viscera]. These fibers are part of Autonomic

nervous system [sympathetic and parasympathetic]

CN 3,7,9,10 In all these 4 cranial nerves fibers belong to parasympathetic

system. While sympathetic GVE fibers exist independent of cranial nerves.

4 kinds of Sensory fibers4 kinds of Sensory fibers::1.GSA [general sensory]1.GSA [general sensory]

General Somatic Afferent GSA fiber is one whose cell body [pseudounipolar

neuron] lies outside CNS in dorsal root sensory ganglion or sensory ganglions of cranial nerves.

Central limb of this neuron goes to CNS to specific nucleus in brainstem

Peripheral limb of this neuron goes to somatic receptors in skin, skeleton muscle, tendons or joints.

The sensory receptors responsible for sensations like, touch, pain, temperature, pressure, proprioception etc.

CN 5,7,9,10 Also note that all 31 spinal nerve have this GSA component.

2.GVA [visceral sensory]2.GVA [visceral sensory]

General Visceral Afferent Part of Autonomic nerves [sympathetic

and parasympathetic] Receptors are on mucus membrane and

wall of internal organs [viscera] Carry sensations like, burning, fullness,

pain [not specific and poorly localized], thirst, hunger, general unpleasantness etc. + chemoreception for cardio-respiratory regulation

CN 9,10

3.SSA [special sensory -1]3.SSA [special sensory -1]

Special Somatic Afferent Fibers associated with special senses

of Vision and Hearing+ Balance. Associated with highly specialized

somatic receptors stimulated by non-chemical changes like light or mechanical movements: Retina in eye and auditory receptors in ear

CN 2, 8

4.SVA [special sensory – 2]4.SVA [special sensory – 2]

Special Visceral Afferent Fibers associated with special senses

of Taste and Smell Receptors are highly modified special

receptors which detect CHEMICAL changes.

CN 1,7,9,10