Sensory retina
The photosensitive portions of rods are embedded deep in the pigment epithelium and are filled with membranous discs that contain the visual pigment, rhodopsin. These discs are formed continuously by repetitive in-folding of the plasma membrane of the rods and by synthesis of proteins in its inner segment. Discs are exfoliated distally and are phagocytosed by the pigment epithelial cells. 400x, 20,000x
Rod outer segments
The photosensitive portions of rods are embedded deep in the pigment epithelium and are filled with membranous discs that contain the visual pigment, rhodopsin. These discs are formed continuously by repetitive in-folding of the plasma membrane of the rods and by synthesis of proteins in its inner segment. Discs are exfoliated distally and are phagocytosed by the pigment epithelial cells. 400x, 20,000x
Membranous discs
The photosensitive portions of rods are embedded deep in the pigment epithelium and are filled with membranous discs that contain the visual pigment, rhodopsin. These discs are formed continuously by repetitive in-folding of the plasma membrane of the rods and by synthesis of proteins in its inner segment. Discs are exfoliated distally and are phagocytosed by the pigment epithelial cells. 400x, 20,000x
Pigment epithelium >
It takes about 10 days for newly formed discs to reach the end of the outer segment, where they are shed and phagocytosed by cells of the pigmented epithelium. Note the intact distal segment of a rod surrounded by long, thin processes of the pigment epithelium cells; packets of phagocytosed discs are visible in the pigment epithelium cell.
- Cell processes
It takes about 10 days for newly formed discs to reach the end of the outer segment, where they are shed and phagocytosed by cells of the pigmented epithelium. Note the intact distal segment of a rod surrounded by long, thin processes of the pigment epithelium cells; packets of phagocytosed discs are visible in the epithelial cytoplasm.
- Phagocytosed disc membranes
It takes about 10 days for newly formed discs to reach the end of the outer segment, where they are shed and phagocytosed by cells of the pigmented epithelium. Note the intact distal segment of a rod surrounded by long, thin processes of the pigment epithelium cells; packets of phagocytosed discs are visible in the epithelial cytoplasm.
- Melanin pigment
It takes about 10 days for newly formed discs to reach the end of the outer segment, where they are shed and phagocytosed by cells of the pigmented epithelium. Note the intact distal segment of a rod surrounded by long, thin processes of the pigment epithelium cells; packets of phagocytosed discs are visible in the epithelial cytoplasm.
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