Unit 2 Flashcards
Cranial nerve II
Optic nerve
-sensory: vision
Cranial nerve III
Ocularmotor nerve
(IR, SR, MR, IO)
motor:
-eye movement
-eyelid opening
-pupil constriction
-accommodation
Cranial nerve IV
Trochlear
Motor: eye movement
Superior oblique muscle
Cranial nerve VI
Abducens
Motor: eye movement
Innervates lateral rectus muscle
Cranial nerve V
Trigeminal
(3 divisions but we only need to know V1: ophthalmic (broken into 3 subsections)
-Frontal: Innervates forehead, upper eyelids, sides of nose
-nasociliary: cornea, iris, ciliary body
-lacrimal: lacrimal gland, skin of upper eyelid, conjunctiva
CN III superior and inferior innervations
Superior:
-levator palpebrae superioris
-superior rectus (SR)
Inferior:
-Medial rectus (MR)
-inferior rectus (IR)
-inferior oblique (IO)
-pupil constriction
-accommodation
CN V innervations
Ophthalmic nerve (V1)
-frontal (forehead, upper eyelids, sides of nose)
-lacrimal (lacrimal gland, skin of upper eyelid, conjunctiva)
-nasociliary (cornea, iris, ciliary body)
-long ciliary
-short ciliary
(Bony orbit) location of frontal bone
Top of eye socket, rest of the forehead
(Bony orbit) location of maxilla bone
Bottom nasal ridge down to top of teeth
(Bony orbit) location of zygomatic bone
Lower temporal region and cheekbones
(Bony orbit) location of sphenoid bone
Right at the back of the eye socket. Can’t miss it.
(Bony orbit) location of ethmoid bone
Entirely within eye socket on the nasal edge, posterior to lacrimal bone
(Bony orbit) location of lacrimal bone
Just inside the eye socket, anterior to ethmoid bone
(Bony orbit) palatine bone
Posterior and inferior to ethmoid bone. It is hiding because it is so little.
Optic foramen
Hole for optic nerve to pass through. Located medial to superior fissure
Superior orbital fissure
Located immediately lateral to the optic nerve
Arterial system
Internal carotid artery
-ophthalmic artery
-central retinal artery
-lacrimal artery
-long posterior ciliary arteries
-short posterior ciliary arteries
-muscular branch
-anterior ciliary arteries
-supraorbital
Venous system
4 to 8 vortex veins drain retina
-inferior vortex vein
-inferior ophthalmic vein
-superior vortex vein
-central retinal vein
-superior ophthalmic vein
-lacrimal vein
Short posterior ciliary arteries
Enter the posterior of the sclera
Long posterior ciliary arteries
Run medially and laterally along the sides of the optic nerve and pass to the anterior aspect of the eyeball
Anterior ciliary arteries
Branches off the long posterior artery and supplies anterior portion of eye
Central retinal artery
Supplies interior surface of the retina. Branches off of ophthalmic artery. Pierces the optic nerve to enter the retina at the optic disc.
Vortex veins
4-8 veins that drain the retina. Are located superiorly and inferiorly. drain into the superior and inferior veins
Superior and inferior veins drain into
Cavernous sinus
Cavernous sinus
Two Big-ass chambers that pretty much everything passes through to get to your eyeball
Central retinal vein
Accompanies the central retinal artery to drain blood from the retina inside the eye.
Posterior pole diagram
(Know where these are, I can’t put em here)
-Optic nerve
-superior arcade
-inferior arcade
-temporal retina
-nasal retina
-retinal vein
-fovea
-macula
6 Extraocular muscles + CN nerves
-superior oblique (CN IV)(trochlear)
-superior rectus (CN III) (oculomotor)
-medial rectus (CN III)
-lateral rectus (CN VI)(abducens)
-inferior oblique (CN III)
-inferior rectus(CN III)
Visual pathway of light through the eye
-cornea
-anterior chamber
-pupil
-posterior chamber
-lens
-vitreous humour
-macula
-fovea
-optic nerve
Layers of the cornea
-Epithelium (most anterior)
-Bowman’s layer
-stroma (thickest)
-descemet’s membrane
-endothelium (most posterior)
Endothelium
Most posterior layer of cornea. Is “leaky”: allows water to pass from aqueous. Pumps fluid out from stroma to anterior chamber
2 types of Conjunctiva
Bulbar-covers sclera
Palpebral- covers inside of eyelid
Sclera
-Made of collagen
-visible white part of eye
-goes all the way around eyeball
Ciliary body
Anterior
-Controls accommodation
-produces aqueous
-anchors zonules
Trabecular meshwork and canal of schlemm
-Anterior
Filter aqueous fluid
Iris
Anterior
-Dilation and constriction of pupil
Crystalline lens
Anterior
-65% water
-3 layers
-nucleus
-cortex
-capsule
-biconvex lens
-plus power for eye
-accommodation
Vitreous humour
Posterior
-mostly water, some collagen
-cloquet’s canal
-allows light to pass through
Choroid
Posterior
-Large vessels
-choriocapillaris
-supply retina with oxygen, transport nutrients to and from retina
Layers of retina-(starting from vitreous)
Internal limiting membrane
Nerve fiber layer
Ganglion cell layer
Inner plexiform layer
Inner nuclear layer
Outer plexiform layer
Outer nuclear layer
External limiting membrane
Photoreceptor layer
Retinal pigment epithelium (RPE)
Bruch’s membrane
Retinal blood supply from
-Choriocapillaris
-central artery branches
Function of retinal pigment epithelium (rpe) (posterior layer)
-melanin absorbs stray light
-transport of metabolites
-barrier to protect photoreceptors
-regeneration of rods and cones
-phagocytosis of photoreceptor tips
3 parts of Uveal tract
-iris
-ciliary body
-choroid
Primitive embryonic layers
-surface ectoderm
-neural crest
-neural ectoderm
-optic vesicle
-optic cup
-Endoderm
-where? Get fucked, that’s where, I guess.
Extraocular muscles that are not innervated by CN III
Superior oblique - IV trochlear
Lateral rectus - VI abducens
Cranial nerves pass through this fissure
Superior fissure
Extraocular muscle innervated by CN IV (trochlear)
Superior oblique
Extraocular muscle innervated by CN VI (abducens)
Lateral rectus
Cranial nerve VII
Facial
Sensory and motor
Facial expression, parasympathetic innervations of lacrimal and salivary glands
Embryonic development week 3
Neural groove
Between which weeks of gestation does the majority of ocular development occur?
Between three and 10 weeks
Three embryonic layers of the eye
– Surface ectoderm
– neural ectoderm
– mesoderm
NO ENDODERM 
Embryonic development week four
– Optic vesicles
– lens plates
Embryonic development week five
– Optic cup
– lens vesicle
Embryonic development week six
– Cornea
– hyaloid vessels
– vitreous cavity
– lens separates
Embryonic development week seven
– Retina differentiates from neural and pigment
– sclera
– optic nerve forms
Embryonic development week eight
Extraocular muscles
Describe infant cornea
Large cornea at birth reaches adult size by two years old
Describe infant iris
Heavily pigmented posterior Iris but less or no pigment in the anterior Iris. often appears blue
What is Coloboma
A congenital malformation due to failure of an embryonic structure to fuse
The general shape of the orbit moving from front to back
Pyramidal
Three bones that contribute to the orbital rim
– Frontal
– zygomatic
– maxilla
Cranial nerves pass through this opening
Superior orbital fissure
Superior ophthalmic vein empties here
Cavernous sinus
Lamina cribrosa
Posterior mesh area that nerve fibres travel through
Limbus
Area immediately around the cornea
Choriocapillaris
Capillaries coming from the choroid
Canaliculi
Tubes connected to puncta to drain tears
