Ocular Anatomy: Intro to Eye

what does the visual system do

takes information from environment in the form of light and analyzes and interprets it so the organism can see

what tissues hold the eye and protect it

bony tissue

fatty tissue

connective tissue

anatomical orientations of eye:

sides of eye/orientation of eye

nasal side/ temporal side

anterior pole/posterior pole

outer to inner layers of eye (superficial to deep):

outer fibrous tunic

middle vascular tunic

inner neural tunic

what does the fibrous tunic (outermost tunic) consist of

cornea - front has to be clear to see

limbus - transition zone

sclera - white of eye

(blue)

whats the function of the fibrous tunic

protection

cornea

clear cap, so light can enter

limbus characteristics

transition zone between cornea and sclera

sclera characteristics

white of eye

opaque, fibrous, tough protective outer layer of the eye

continuous w the cornea and w the sheath covering of the optic nerve

middle tunic (uveal/vacular tunic) components

iris

ciliary body

choroid

(red)

highly vascularized

iris characteristics

gives eye color

ciliary body characteristics

muscle; lets us focus light

continuous w iris and choroid, triangle shape

can not be seen unless patient is imaged

choroid

vascular layer of eye lying between retina and sclera

Inner tunic (Nervous Tunic) components

sensory retina

retinal pigmented epithelium - not shown

(yellow)

sensory retina characteristics

nervous tissue

converts light into a stimulus that is transmitted to the brain to be interpreted as an image

fovea

in inner tunic and is an indentation that gives us sharp vision

retinal pigmented epithelium

support layer to sensory retina

name the tunics and parts in the histological section

structures in anterior portion of the eye

cornea

limbus

anterior sclera

anterior chamber (aqueous humor)

iris

lens (suspensory ligament)

ciliary body

posterior chamber (aqueous humor)

anterior chamber

behind cornea and in front of lens

filled w aqueous

zonules

fine fibers that attach to lens, do not pick up stain

lens characteristics

transparent football shaped

posterior chamber

behind iris and adjacent to lens

filled w aqueous

anterior sclera

forward part of sclera

posterior region of eye components

sclera - posterior region

choroid

retina

vitreous humor - filling vitreous chamber

fovea

optic nerve

chambers of the eye include:

anterior chamber

posterior chamber

vitreous chamber

aqueous

fluid, gives avascular tissues nutrients and removes waste

vitreous chamber

behind lens

largest chamber

filled w vitreous gel

maintains eye shape

eyelids

protect the eyes

thin layer of epithelial tissue - skins of upper and lower eyelids are the thinnest layers of skin in the body

eyelid fxns

protect eye from foreign bodies

blinks as a reflex

helps to spread tears

limit light entering the eye

nasolacrimal system function

produce tears via the lacrimal gland

drain the tears via the drainage system —> empties into nasal cavity

—> when you cry your nose runs

functions of cornea

transparency - to focus light

refractive power

protection

conjunctiva characteristics

thin, transparent layer of cells which cover the sclera and inner eyelid

conjunctiva function

protect the sclera from organisms

produce part of the tear film

provide nutrition and lubrication to the cornea

sclera fxn

provide protection

maintains shape of eye

eye muscles attach to sclera

limbus fxn

area where fluid of eye drains

---

via the canal of schlemm

iris functions

controls the size and shape of the pupil (and illumination to the retina)

gives eyes their color

ciliary body fxn

produces aqueous or fluid of the anterior and posterior chambers

ring of muscle that changes shape of lens to maintain focus

lens fxn

focuses light rays onto retina

can become cloudy and develop cataracts

choroid fxn

nourishes the outer layers of the retina

prevents reflection of light (highly pigmented)

retina fxn

receives light - has light sensitive cells (rods and cones)

converts light to visual energy

transmits light

fovea characteristics

area of retina where light is focused for clear vision

fovea fxn

gives us our clear vision and color vision(cones)

optic nerve characteristic

extension of the last layers of the retina

optic nerve fxn

transmits nerve impulses from retina ultimately to visual cortex

where is the blind spot?

at the optic disc - where the optic nerve leaves the eye

name the parts

red is the sensory retina w the blood vessels