Choroid Flashcards
What is Choroid
Starts where CB ends. Lines sclera from ora serrata to the edge of optic disk.
Highy vascular and provides a route for metabolites to anterior eye. Provides oxygen and nutrients to retina and removes waste products from retina.
Highly pigmented means absorbs light that passes through retina which stops it bouncing around eye or reflecting eye so protects it from damage.
Suprachoroid -1
Transition zone between sclera and choroid. Made up of collagen fibres continuous with those old sclera and menalocytes and fibroblasts.
Carries nerves and blood vessels not and from anterior eye.
Nerves that terminate at choroid are derived From short posterior ciliary nerves.
Stroma- 2
makes up bulk of choroid.
pigmented layer containing mainly blood vessels .melanocytes and fibroblasts and collagen also present.
Microphages- phagocytic cells which are cells that digest dead and dying cells and recycles them- filled with pigment and lymphocytes are also present.
Blood vessels in this layer are split into 2 layers-
An external layer with bigger blood vessels- Hullers Layer
An internal layer with smaller blood vessels- Sattlers layer
Choriocapilliaris -3
Layer of capillaries ln unusual organisation lying against basal lamina instead of distributed throughout tissue.
Unusally wide 30 microns thick.
Collagen fibres present between capillaries with fibroblast unmyelinated nerve fibres.
FREE OF PIGMENT.
Basal Lamina - Buchs Membrane -4
Innermost layer- has outer elastic and inner cuticular lamina.
inner cuticular lamina provides smooth surface for RPE.
Connected to choroidal stroma by collagen fibres that pass between the capillaries of choriocapiollaris
With ageing cuticular layer of Bruchs membrane may thicken to form mounds called druse which contains granular material believed to be secreted by retina pigment epithelial cells.
Blood supply
Receives arterial blood from branches of the short posterior ciliary arteries via recurrent arteries from MAC
