Functions Of Choroid And Aging Changes In The Uvea Flashcards
Middle layer of the eye
Uvea
Three regions of uvea
Iris
Ciliary body
Choroid
Choroid extends from ______ to _______
Ora serata to optic nerve
Choroid is located betwee the _____ and the ______
Sclera and retina
What kind of choroid absorbs excess light
Darkly pigmented choroid
This membrane of the choroid fuses with the retina multi laminated sheet
Bruchs membrane
This type of choroid provides nutrients to and remove the waste products from outer retina
Vascular choroid
Watershed layer of the retina
Outer plexiform layer
What separates the outer retinal layer from the inner retinal layer
Outer plexiform layer
Layers of the retina in the fovea
Area devoid of vessels
What is the sole blood supply to the fovea avascular zone
Cchoriocapillaris
Provides a pathway for the posterior vessels that supply the anterior segment
Suprachoroidal space of choroid
________ nerve carries sensory and sympathetic fibers
Long ciliary nerve
_____nerves carry sympathetic and parasympathetic fibers
Short ciliary nerves
Choroid changes in emmetropization: hyperopia refocus
Thin choroid, growth increased
-can rapidly modulate its thickness, in so doing, varying the position of the retina and thus the state of focus of the eye
Choroidal changes in emmetropization in myopic defocus
Thick choroid, growth decreased
Functions of choroid
Provide nutrients and remove the waste products from outer retina
Passage of nerves and vessels
Absorption of excess light
Regulate emmetropization
Aging changes in iris
Loss of pigmentation
Dilator muscle beceoms atrophic
Sphincter muscle becomes sclerotic
Difficult to dilate elderly
Aqueous humor and age
Decreases, by 80, approximately 25% of what it was
Aginging changes in choroid
- choroicapillaris decreases in density and diamter, then choroidal blood flow decreases
- bruchs membrane increases in thickness
- various substances and particles accumulates in bruchs membrane
Nutrients from the choriocapillaris and waste produce from the retina must pass though
Bruchs membrane
Layers of bruches membrane
- Interrupted BM
- Outer collagenous zone
- Elastic layer
- Inner collagenous zone
- BM of RPE cels
Calidification and the yellow deposits in the inner collagenous layer of Bruchs membrane. Made of the remaining cells (lipofuschin) from oxidative stress
Drusen
Hello brown pigment granules composed of lipid containing residues from oxidativestress
Lipofuscin
Accumulation of Drusen in Bruchs
Makes bruchs hydrophobic and presents a barrier to water movement, inhibiting the passing of metabolites
-water accumulation between RPE and Bruch’s membrane cause detachment
AMD causes
Age, genetics, lifestyle
DRY
-extensive soft confluent Drusen throughout the macula with subtle RPE drop out
EARLY WET
-acute subretinal blood in macular area with subtle sub-retinal fluid; choroidal neovascularization membrane (CNVM) is not clearly visualized
LATE WET
-subretinal blood, CNVM and sub retinal fibrosis with RPE atrophy in macular area
Which layer is multilaminated sheet and fuses with RPE
Bruchs membrane
Which one proves blood to fovea region
Choriocapillaris
Which part of retina receives blood supply from choroid
Outer retina
Which layer of choroid proves a pathway for the vessels and nerves that supply the anterior segment
Suprachoriudal space
Which change to bruchs membrane with aging (thickness)
Increases
Which layer of bruchs membrane does druse deposit
Inner collagenous zone
