Special Senses Eye Flashcards
What are the two division of the eye?
functional
anatomical
what makes up the functional division?
sensory - retina
dioptric - cornea, ant/post chambers, lens, vitreous body
what makes up the anatomical division?
walls -tunica externa/fibrosa -tunica media/vasculosa -tunica interna/nervosa lens ant/post chambers vitreous body
what makes up the tunica externa/fibrosa?
sclera and cornea
what makes up the tunica media/vasculosa?
chrooid
ciliary body
iris (uvea)
what makes up the tunica intern/nervosa?
retina
what makes up the corneoscleral coat (tunica fibrosa?) 3 main modifications
cornea - anterior
substantia propria - middle
area cribosa - posterior
what is found in the substantia propria?
collagen fibers
vascular
what is the area cribrosa?
perforated for passage of optic nerve and retinal vessels
are blood vessels found in cornea?
NO
what has the richest sensory supply?
cornea - thats why it hurts so bad when it gets scratched
what are the 5 layers of the cornea? (mneumonic ABCDE)
- anterior corneal epithelium
- bowman’s membrane
- corneal stroma
- Descemet’s membrane
- posterior corneal endothelium
what type of epithelium is found int he anterior corneal epithelium? what are some characteristics
stratified squamous epithelium - 5 layers about
has microvilli on superficial cells
basal cell mitotic activity - regen
free nerve endings
how long does it take for cells in teh anterior corneal epithelium to regenerate?
7 days for basal cells to reach the surface - thats why a patch over eye for 7 days is good!
what are the characteristics of Bowman’s membrane?
homogenous collagen fibers
no cells!!!!
provides strength and stability
does NOT regen
what are characteristics of corneal stroma?
- 60 lamellae each make of collagen fibrils
- fibroblasts and keratoniocytes between lamellae to produce GS
- keratin and chondroitin sulphates for ECM
what is a keratoplaty
alter the stroma of the cornea
what are characteristics of Descemet’s membrane?
homogenous collagen filaments
meshwork of collagen
fenestrations between stroma and corneal endothelium
what are characteristics of the posterior corneal endothelium?
- simple squamous cells
- abundant sodium pumps
- maintains optimum hydration of corneal stroma
what is the sclera?
dense CT extension of dura
collagen (type I) and elastic fibers
what are the 3 layers of the sclera?
Episcleral layer
substantia propria
suprachoroidal lamina
what is Tenon’s space?
between episceral layer and substantia propria
site of attachment for ocular muscle
what is the limbus?
junction between the cornea and sclera
what are features of the uvea?
vascular
loose CT
pigmented cells - to absorb excess light that enters the eye
what are distinguishing features of the choroid?
lots of melanocytes
very vascular
what are the 3 layers of the choroid?
- choroid proper - large BV
- chorio capillary layer - continuous cap
- Bruch’s membrane
what is bruch’s membrane?
between choroid nad retinal pigment layer
component of the blood retinal barrier
what does the ciliary body consist of?
cilliiary muscles
ciliary processes
what is the function of hte ciliary muscle?
orientation - radial and circular
contraction/relaxation changes the shape of the lens
accommodation - near and distant vision
innervated by ciliary nerves
what is the function of ciliary processes?
- provide attachment to the capsule of lens by means of zonule fibers (anchor of lens) (ligaments of Zinn)
- secretion of aqueous humor (non pigmented epithelium)
- characterized by the presence of fenestrated capillaries!!!!!!
what type of fibers are zonule fibers?
elastic (oxytalan) - this is why you get sublux of lens with Marfan syndrome!
what is the iris?
loose CT
pigmented
anteiror extension of choroid - 3rd part of uvea
forms diaphragm with pupil in center
separates ant from post chamber
what types of cells line the anterior iris?
epithelial cells
stellate fibroblasts
stellate melanocytes
what makes up the stroma of iris
collagen
fibroblasts
malanocytes
what makes up the posterior surface of the iris?
inner (posterior) epitheium - pigmented (cont of RPE)
outer epithelium - pigmented myoepithelium cells - makes up dilator pupillae muscles
where is sphincter pupillae muscle?
tip of iris
innervated by PNS CN 3
what is the sclerocorneal junction?
canal of Schlemm - aqueous humor is drained into ciliary veins!
what is the retina derived from?
ectoderm
what are the 2 basic layers of the retina?
outer retinal pigment epithelium - not sensory
inner sensory retinal/neural retina
is the anterior porition of the retina photosensitive?
no
what is the Ora serrate?
joins the outer layer and inner layer - runs around periphery
what are characteristics of the pigment epithelial layer?
- single layer of cuboidal cells
- synth melanin
- cells connected by right junctions
- lots of Mv - phago. shed disc of rod/cones
- est. blood retinal barrier
- esterification of vit. A
what are rods?
rhodopsin - (opsin -scotopsin)
opsin + chormatophore (vit. A dervied carotensoid –> retinal)
night blindess?
black and white vision
120 mil
what are cones?
7 mil
thicker, shorters
disc has pigment iodopsin (opsin-photopsin)
color vision
what are the 4 layers of the retina
pigment epithelial layer
outer nuclear layer
inner nuclear layer
ganglion cell layer
what are conducting cells of sensory receptors? (mneumonic BHAN)
biopolar, horizontal, amacrine, nuclei of muller cell
how does layers 1-5 get BS?
chorio cappilaries by diffusion
how does layer 6-10 get BS?
central retinal a.
what is the optic disc?
where optic n. emerges from retina
“blind spot” - no rods or cones
what is fovea centralis?
max cones
what is macula lutea?
yellow area near fovea - rich in cones
color due to xanthophyll pigment
what are the 3 components of the lens?
lens capsule
subcapsular epithelium
lens fibers
what does the vitreous body contain?
hyalocytes - hyluronic acid
what is the conjuntiva?
inside of eyelids
secretes mucin
what are the glands of the eyelid?
meibomian glands
glands of Zeiss
glands of Moll
when do you get a sty?
when gland of zeiss or moll is obstructed
what are the 4 layers of the retina
pigment epithelial layer
outer nuclear layer
inner nuclear layer
ganglion cell layer
what are conducting cells of sensory receptors? (mneumonic BHAN)
biopolar, horizontal, amacrine, nuclei of muller cell
how does layers 1-5 get BS?
chorio cappilaries by diffusion
how does layer 6-10 get BS?
central retinal a.
what is the optic disc?
where optic n. emerges from retina
“blind spot” - no rods or cones
what is fovea centralis?
max cones
what is macula lutea?
yellow area near fovea - rich in cones
color due to xanthophyll pigment
what are the 3 components of the lens?
lens capsule
subcapsular epithelium
lens fibers
what does the vitreous body contain?
hyalocytes - hyluronic acid
what is the conjuntiva?
inside of eyelids
secretes mucin
what are the glands of the eyelid?
meibomian glands
glands of Zeiss
glands of Moll
