Lecture 33: Eye Flashcards
- levator palpebrae superioris muscle
2.tarsal plate
3.cornea
4.conjunctiva
what is inner surface of eyelids lined with
conjunctivate. specialized mucous membrane. note: doesn;t cover cornea
tarsal plate
2 in image
cartilage forming the skeleton of eyelid.
provides insertion point for levator palpebrae superioris
sebaceous glands embedded in plates
levator palpebrae superioris nerve supply
CNIII and sympathetic fibres
cornea
anterior transparent part eyeball
- ciliary body
2.suspensory lig - pupil
4.cornea
5.iris
what are the 3 layers of eyeball from outside to inside
- Fibrous layer: made of fibrous tissue. Most of posterior part of fibrous layer (5/6) is made of dense irregular connective tissue = sclera. This layer is there to mechanically protect eyeball. Attachment site for E.O. muscles
* Anterior 1/6 of fibrous layer turns into clear/transparent layer=cornea. Clear due to Due to arrangement collagen fibres AND no blood vessel flowing into it- Vascular layer: posterior 5/6 is called choroid. Brings blood vessels to nourish retina
- Anteriorly divides into:
§ Ciliary body: made of smooth muscle fibres.
□ Attached to lens by suspensory ligaments- hold lens in place and change convexity of lens
§ Iris: made of smooth muscle fibres.
□ At center of iris= pupil
□ Fxn iris= expand or reduce size of pupil
- Anteriorly divides into:
- Nervous layer: posterior 3/4 is called retina. Loaded with photoreceptors convert light to nerve impulses
- Anterior 1/4 is pigmented epithelium. Covers ciliary body. Lines posterior surface iris.
§ Determines colour of eye
§ No pigment= blue eyes
Optic nerve (CNII) axons retina
- Anterior 1/4 is pigmented epithelium. Covers ciliary body. Lines posterior surface iris.
- Vascular layer: posterior 5/6 is called choroid. Brings blood vessels to nourish retina
fibrous layer of eyeball
- Fibrous layer: made of fibrous tissue. Most of posterior part of fibrous layer (5/6) is made of dense irregular connective tissue = sclera. This layer is there to mechanically protect eyeball. Attachment site for E.O. muscles
* Anterior 1/6 of fibrous layer turns into clear/transparent layer=cornea. Clear due to Due to arrangement collagen fibres AND no blood vessel flowing into it
vascular layer eyeball
=middle layer
- Vascular layer: posterior 5/6 is called choroid. Brings blood vessels to nourish retina
* Anteriorly divides into:
§ Ciliary body: made of smooth muscle fibres.
□ Attached to lens by suspensory ligaments- hold lens in place and change convexity of lens
§ Iris: made of smooth muscle fibres.
□ At center of iris= pupil
□ Fxn iris= expand or reduce size of pupil
nervous layer eyeball
=inner
- Nervous layer: posterior 3/4 is called retina. Loaded with photoreceptors convert light to nerve impulses
* Anterior 1/4 is pigmented epithelium. Covers ciliary body. Lines posterior surface iris.
§ Determines colour of eye
§ No pigment= blue eyes
Optic nerve (CNII) axons retina
is pupil dilated by symp or para?
symp! maximized light entry into eye
- macula lutea
- optic disk
- fovea centralis
blind spot
=optic disk
no PRs
macula lutea
“yellow spot”
at centre is fovea centralis- higest [PRs]
blood supply eye
choroid
what happens to lens when looking at near object
lens is super convex.
ciliary body contracts
suspensory ligaments are loose
PSN
what happens to lens when looking at far object
ciliary body relaxed
lens is flat
sympathetic NS causes this
what muscles is iris comprised of
2 sets smooth muscles:
- sphincter pupillae aka circular. reduce pupil size. PSN stimulates
- dilator pupillae/radial muscles, symp
1.scleral venous sinus
2. anterior chamber
3.ciliary body
4.posterior chamber
5. vitreous chamber
space btw cornea and iris
ant chamber
space btw iris and lens
post chamber
what connects anterior and posterior chamber
pupil
what is purpose of anterior and posterior chamber
Both chambers filled with aqueous humour. Produced by ciliary body (to make sure cornea/lens are clear, they have no blood vessels) SO this aq. Humor nourishes cornea/lens
venous drainage eye
scleral venus sinus at junction of cornea and sclera drains the aqeuous humour
vitreous chamber
btw lens and retina
filled with vitreosus fluid which shapes eyeball and cushions retina
glaucoma
extra pressure in ant/post chambers –> transfers to retina thru vitreous body
1.nasolacrimal duct
2.lacrimal canaliculus
3.lacrimal gland
4.lacrimal sac
lacrimal gland
upper lateral corner eye. produces tears. controlled by CN VII
where do tears go after being produced by lacrimal gland
collected in lacrimal sac. in medial corner eye
lacrimal canaliculus
two ducts which drain from lacrimal lake to lacrimal sac
where does lacrimal sac connect
nasolacrimal duct. drains tears to inferior meatus, nasal cavity
which bones is lacrimal sac btw
lacrimal and maxilla
what % of cerebral cortex is devoted to processing visual info
40
sclera
posterior 5/6 fibrous layer. dense connective tissue. protects inner eyeball. attchment site for EOM
cornea
ant. 1/6 fibrous layer
transparent, no blood vessels, covered by conjunctiva. convex anteriorly, helps focus light on retina
choroid
forms the posterior five sixth of the vascular
layer and lines the inner surface of the sclera. It is highly
vascularised and nourishes the retina. The choroid carries
melanin pigments that absorbs the light rays and prevents the
reflection of light within the eyeball.
ciliary body
anterior continuation of choroid. secretes aq. humour, modifies convexity of lens
iris
anterior 1/6 vascular layer. smooth muscles that determine amount light entering eyeball
retina
posterior 3/4 of nervous layer
what determiens colour of eye
anterior 1/4 of nervous layer. pigmented epithelium. covers ciliary body. lines posterior surface iris
