Anatomy of the Retina

From the edge of the optic disc to the ora serrata/ciliary body

Neural ectoderm

Photoreceptors, horizontal cells, bipolar cels, amacrine cells and ganglion cells

RPEPhotoreceptor layerExternal limiting membraneOuter nuclear layerOuter plexiform layerInternal nuclear layerInner plexiform layerGanglion cell layerNerve fiber layerInternal limiting membrane

Single layer of pigmented cells in which the apical side faces the retina: basal side lies adjacent to the BM that is shared by Bruch's membrane. RPE cells are highly active and therefore contain many organelles, including smooth and rough ER, Golgi, lysosomes, and pigment cells: including melanosomes and lipofuscin (for phagocytosis)

The outer layer of the optic cup: It contains a BM that clings to Bruch's membrane. Thus it has a tight connection with the choroid, but is loosely adherent to the retina.

The fact that the retina is tightly attached to Bruch's membranne, but loosely adherent to the retina. This creates a space between the RPE and neural retina (subretinal space) that can lead to retinal detachments.

1. Phagocytosis of photoreceptor outer segments2. Transport of ions, water, and metabolites between the choroid and retina

120 million rods/6-8 million cones. These are special sensory cells whose photo-pigments absorb photons of light. They contain an outer and inner segment.

Make the discs that surround the photopigment molecules. The outer segment of both rods and cones contain hundreds of lipid bilayered discs that are surounded by a cell membrane.

Make the photopigments, which are then transported to the outer segment, via the cilium, where they are incorporated into discs.

1. Myoid: Inner layer of inner segment: location of protein synthesis. this part contains RER and golgi. Remember the myoid region makes protein. 2. Elipsoid: outer layer of inner segment. packed with mitochondria. Remember, the elipsoid (energy) region is high in mitochondria.

Hundreds. Each disc contains thousands of photopigment molecules that are responsible for the absorption of light. The photopigment in rods is called rhodopsin. in cones, iodopsin.

In rods, the photopigment is called: rhodopsinin cones, the photopigment is called: iodopsin

scotopic vision: detects objects at low levels of illuminationRod density is greatest about 5mm concentrically from the fovea in an area known as the rod ringRod discs contain rhodopsin, which absorbs photons maximally at 507 mn. Does not detect color.