Exam2Lec4Eye Flashcards
What is the function of the eye?
- Regulation of the amount of light entering the eye
- Focusing of light to form an iamge
- Conversion of light into neural activity
- Analysis of the visual image before relaying information to the brain
Whate are the chambers of the Eye?
- Anterior chamber
- Posterior chamber
- Vitreous chamber
What is the ant. chamber defined by and what is it filled with?
- space defined by the cornea, iris and lens (post. to cornea and ant. to iris +lens)
- Filled with aqueous humor
What is the post. chamber defined by and what is it filled with?
- Spaced defined by the iris, lens, zonule fibers and cilary body (post to iris, anterior to lens+ ciliary body)
- Filled with aqueous humor
What is the vitreous chamber defined by and what is it filled with?
- Space defined by the lens, zonule fibers and retina (post. to lens+ciliary body, ant to retina)
- Filled with gelatinous vitreous humo (separate from aqueous by density)
What are the layers of the eye?
- Outer layer: corneo-scleral layer (fibrous)
- Middle: Choroid layer (vascular and pigmented)
- Inner: retinal layer (neural)
What is contained within the outer layer of the eye?
- Cornea-> covers outer anterior surface
- Sclera-> covers the outer post. surface
Corneo-scleral layer
What is contained in the middle layer of the eye? Fxn?
- Iris-> gives the eye its color
- Ciliary body-> connects to the lens for fine focusing
- Choroid-> loose CT lining the inside (beneath sclera)
What is the purpose of pigment in the middle layer of the eye?
to absorb light, if there is no pig. then the light will be reflected
What is contained in the inner layer of the eye? fxn?
- Retinal pigment epithelium-> outer layer of retina
- Neural retina-> inner layer containing nerve cells
- Fovea (macula)-> area of greatest visual acuity⭐️
- Optic disk-> bind spot; where optic n exits the eye⭐️
What is the area of greatest visual acuity?
What is the bind spot?
- Fovea (macula)-> area of greatest visual acuity⭐️
- Optic disk-> bind spot; where optic n exits the eye⭐️
What are the 5 layers of the cornea from superficial to deep?
- epithelium
- Bowman’s membrane
- Stroma
- Descernet’s membrane
- endothelium
What is the type of epithelium in the cornea
stratified squamous epithelium (non-keratinized)
What is the basement membrane of the epithelium in the cornea
Bowman’s (membrane) layer
What is the stroma layer of the cornea?
Dense Reg. CT underlying the basement membrane
What is the basement membrane of the of endothelium?
Descemet’s (membrane) layer)
What is the type of endothelium of the cornea
simple squamous epithelium
What is the fxn of the cornea?
does 75% of the light focusing onto the retina
- vitreous body
- inner retinal layer
- middle choroid
- Corneo-scleral (outer) layer
aqueous humor is produced by what?
ciliary body
Cornea-> _ -> _ -> Brain
Cornea-> lens -> retina->optic n. -> Brain
What are the middle eye structures?
- choroid
- cilary body
- iris
- lens
What is the choroid?
Vascularized and pigmented loose CT
- What is the ciliary body made of?
- What does cilary processes produce?
- what is the fxn?
- Made of smooth muscle cells
- produces aq. humor for ant and post chambers
- fxn: regulates fine focus of lens by adjusting shape via parasympatheitc inn.
- What attached the ciliary body to the lens?
- What happens when the ciliary muscle contracts?
- zonule fibers
- Ciliary muscle contracts-> zonule fibers relax->lens thickens (allows for near-sightedness)
What is the iris made of?
What is the fxn?
- Pigmented loose CT+smooth muscle cells
- fxn: regulation of light entering the eye by changing the size of pupil
How do we change the size of the pupil?
Dilator pupillae contracts-> pupil enlarges-> more light
* Via sympathetic inn
Constrictor pupillae contracts-> pupil shrinks-> less light
* via parasympathetic inn
What is responsible for 25% of light focusing onto the retina?
Biconvex lens
What are the lens layers (outer-> inner)
- Outer layer (capsule)= basement membrane
- Subcapsular layer=simple cuboidal that transitions to columnar epithelium
- Inner layer= lens fibers
* size based on tension of the zonule fibers loacted of ciliary body
What pupillae muscle is around pupil and which one pulls out
around: sphincter pupillae mus
pull out: dilator pupillae muscle
What does the lens provide?
Provides fine focus of visual image by changing shape via ciliary muscle.
What are opacities in the lens
cataracts which can be treated via lens transplant
What happens when you increase aq humor?
glaucoma
When ciliary muscule contracts what happens to lens
decrease tension
What are the 10 layers of the retina? (from vitrous body to choroid)
- inner limiting membrane =INNER
- ganglion cell axons
- ganglion cell bodies
- Inner synaptic (plexiform) layer
- Inner nuclear layer (interneurons)
- Outer synaptic (plexiform) layer
- Outer nuclear layer (photoreceptor cell bodies)
- outer limiting membrane
- rod and cone photoreceptor outer segments
- retinal pigment epithelium =OUTER
What is within the ganglion cell axons layer, ganglion cell bodies ?
- axon: optic nereve fibers from ganglion cells
- bodies: large multipolar neurons synapsing with inner plexiform and axonal process to optic nerve
The inner limiting membrane is what?
basal lamina of muller’s cells
Inner plexiform layer contains what?
neuronal processes
Inner nuclear layer contains what?
nuclei from Muller’s, amacrine, bipolar, horizontal and interplexiform cells (photoreceptor cells)
The outer plexiform layer processes of _ _ cells
photo receptor
The outer nucelar layer form nuclei of _ and _
rods and cones
Outer limiting membrane is formed by what?
formed by row of zonulae adherens from Muller cells
Rods and cones layer are for what?
for light and color
* cones= contain iodopsin-> detect color (red/green/blue)
* Rods= contrain rhodopsin-> detect light/dark
What does the pigment layer of the retina form? What does it do?
forms blood retina barrier, absorbs excess light and phagocytize discs from rods and cone
What is retinal detachment?
separation of the neural retina from retinal pig. epithelium
Light enter the eye and hits what first? then where does it travel through?
- gets focused on the inner limiting membrane
- travels through the retinal layers to reach the rods+cones
What are some roles of the retinal pigment epithelium (mufflys)
- nutritional support for the photoreceptors
- absorbs stray light
- phagocytosis of shed photoreceptor outer segments
What is the role of photreceptors?
phototransduction to convert light into neural activity
What do interneurons do?
process neural signals
What is the role of ganglion cells
transmit visual signals to brain via optic nerve
What is the fovea (macula)?
- back of retina in line with visual axis, specialized to maximize visual acuity
- contains no blood vessels
- all cones-> color vision
- cell spreading to form a pit
What is the optic disk or papillia?
- origin of the optic nerve
- blind spot
- Contains NO photoreceptor cells
What is the ora serrata?
- anterior most border of multilayered neural retina
- **site where photoreceptor cells are 1st observed **
What is macula degeneration?
breakdown of fovea (macula) results in loss of center view
* peripheral view (vision) is still intact
What is the function of the eyelid
functions to protect exposed surface of the eye
What is the outer surface of the eyelid covered by? ⭐️
thin skin (eyelashes)=stratified squamous epithelium (non kert)
What is the inner surface of the eyelid covered by?
conjunctiva= stratified columnar epithelium with goblet cells
What does the eyelid contain
- tarsal plate (fibroelastic connective tissue)
- orbicularis muscle
- large sebaceous Meibomium glands
- small sebaceous Zeis glands-> located at the hair follicle
- Moll sweat glands=apocrine sweat glands
