Choroid

where is the choroid located

between the sclera and retina

where does the choroid extend to and from

it extends to the optic nerve head to the ora serrata

what is the part of the choroid that is in contact with the sclera

suprachoroid

what does the suprachoroid contain

melanocytes

elastic material

fibroblasts

diagonally oriented collagen fibers

what is the suprachoroid the site of for the ciliary body

longitudinal muscle fiber

what is the suprachoroid directly continuous with

supraciliaris

what are the functions of the suprachoroid

allows for blood vessels and nerves to run in it

contains the suprachoroidal space

fastens the choroid to the sclera

what do the diagonal fibers of the suprachoroid allow for

it allows to change thickness within the choroid stroma

what is the widest layer and also the vessel layer of the choroid

stroma

what is the stroma composed of

connective tissue

fibroblasts

antigen presenting cells

melanocytes

what are the 2 types of blood vessels located within the stroma

Haller’s

Sattler’s

which blood vessels are larger

Haller’s

what happens to the blood vessels as you move closer towards the retina

they get more narrow

are the capillaries of Haller’s and Sattler’s fenestrated

no

where is the choriocapillaris layer located

internal to the stroma

describe the capillaries located in the choriocapillaris

single layer of joined capillaries

fenestrated

what wraps around the capillaries of the choriocapillaris

pericytes

what do pericytes do

they control the flow of blood through the vessels by contracting or relaxing

why is it that in the macula and peripapillary areas of the retina there is less of a risk of an ischemic event happening

blocking arterioles doesn’t affect as much because there is a higher arteriole amount compared to venules

where is the retina at a high risk for an ischemic event happening and why

in the equatorial and peripheral areas because there are less arterioles

where are choriocapillaris densest

at the fovea

where is the fovea located

at the very center of the macula

what is internal to the choriocapillaris

Bruch’s membrane

what is the composition of Bruch’s membrane

basement membrane of choriocapillaris (discontinuous)

outer collagenous zone

elastic layer

inner collagenous zone

basement membrane of retinal pigment epithelium

retinal pigmented epithelium

where does Bruch’s membrane taper into

pars plana

what is the retinal pigmented epithelium continuous with

outer pigmented ciliary epithelium

what is the inner non-pigmented ciliary epithelium continuous with

neural retina

what innervates the choroid

sympathetic: vasoconstriction

parasympathetic: vasodilation

some autoregulation: endothelial cells can change tone

what are the functions of the choroid

absorbs stray light due to pigmentation

thermoregulation: light increases temp and choroid can increase and decrease temp

removes waste from retina

blood supplies to photoreceptors

what layer of the choroid allows for bitransport through Bruch’s membrane

retinal pigment epithelium

what controls what goes into the neural retina

blood retinal barrier

what is drusen

collection of basement-like material in inner collagenous zone that creates a nodule outer to retinal pigment epithelial basement membrane

is drusen a pathology

no

does drusen cause vision loss

no but it increases the risk of age-related macular degeneration

if you have drusen build-up in Bruch’s what does that do to the RPE

is causes thinning and death of it