Choroid B6 Flashcards
What is the middle layer of the eye?
Uvea
Uveal tract is composed of 3 regions from back to front?
Choroid
Ciliary body
Iris
The uvea is sometimes called what tunic?
Vascular tunic, because it has the choroid that is composed of mainly blood vessels, which supply the outer retinal layers
The choroid extends from the __________ to the _________ and is located between the _________ and the ___________, providing nutrients to outer retinal layers.
ora-serrata
optic nerve
sclera
retina
Choroid consists primarily of what?
blood vessels, but has a thin connective tissue layer that lies on each side of the stromal vessel layer
The choroid is bordered on both sides by a connective tissue layer, what are they.
Suprachoroid
Bruch’s membrane
Layers of the choroid (from superficial to deep)
Suprachoroid Lamina
Choroidal Stroma
Choriocapillaris
Bruch’s membrane
Suprachoroid lamina is loose, why is this important?
Looseness of the tissue allows the vascular net to swell without causing detachment.
The long posterior ciliary arteries and nerves run in what space to the front of the globe?
Suprachoroidal space (IMPORTANT)
This is a pigmented, vascularized, loose connective tissue layer containing melanocytes, fibroblasts, macrophages, lymphocytes, and mast cells.
Choroidal stroma
Branches of the short posterior ciliary arteries run in what space?
Choroidal stroma
Outer layer of choroidal stroma with vessels that are LARGER
Haller’s Layer
Middle layer of vessels of choroidal stroma with vessels that are smaller and continue to branch into capillary bed.
Sattler’s layer
Sympathetic innervation of choroidal stroma.
Causes vasoconstriction and decreased choroidal blood flow. From sympathetic trunk of carotid plexus via ciliary ganglion
Parasympathetic stimulation of choroidal stroma.
Causes vasodilation, resulting in increased blood flow. Comes from inferior division of CN III via ciliary gang.
Choroidal veins contain no _______.
valves
What are the main drainage of blood in choroidal stroma?
Large vortex pattern
This is a specialized capillary bed, forms a single layer of anastomosing, fenestrated capillaries having wide lumina with most of the fenestrations facing toward the retina.
Choriocapillaris (lamina choroidocapillaris)
These may have a contractile function and are found around the capillary wall. Have ability to alter local blood flow.
Pericytes (rouget cells)
The choroiocapillaris is densest in the ____________ area, where it is the sole blood supply for this small region of the retina.
macular
The deepest/ innermost layer of the choroid.
Fuses with the retina
Runs from optic nerve to ora-serrata
Undergoes modification before continuing into ciliary body
Bruch’s membrane (Basal lamina)
-has a lot to do with macular area and macular degeneration
Composition of Bruch’s membrane: multilaminated sheet containing a center layer of elastic fibers. Outer to inner superficial to deep. What are the 5 layers?
Interrupted basement membrane of choriocapillaris Outer collagenous zone elastic layer inner collagenous zone basement membrane of RPE cells
Fine filaments from the _____________ of the Retinal pigmented Epithelium (RPE) merge with the fibrils of the inner collagenous zone, makes tight adhesion with choroid and pigemented layer of retina.
basement membrane (important in retinal detachment)
3 functions of choroid?
Provide nutrients to outer retina
Absorbs excess light
Pathway for the posterior vessels and nerves that supply the anterior seg
Explain some of the uveal blood supply and venous drainage.
Short posterior ciliary arteries enter the globe in a circle around the optic nerve, and their branches form the choroidal vessels.
Venous drainage for most of the Uvea is through Vortex veins
Sensory innervation of Uvea is provided by?
Nasociliary branch of CN 5 V1
With aging, excessive basement membrane (basal lamina) material is deposited in the collagenous zones of Bruch’s membrane. These deposits in the inner collagenous zone is called _________.
Drusen
Cones are good at
Macula, color, and precision
Rods are good at
Light and motion
