the blood vessels that supply the retinal cells lie in the optic disc.
the blood vessels that supply the retinal cells lie in the optic disc.
where do the blood vessels that supply the retinal cells lie?
the optic disc
in section, the retina is no more than 0.5 mm thick. it has three layers of nerve cells and two of synapses, including the unique ribbon synapse. the optic nerve carries the ganglion cell axons to the brain, and the blood vessels that supply the retina. the ganglion cells lie innermost in the eye while the photoreceptive cells lie beyond. because of this counter-intuitive arrangement, light must first pass through and around the ganglion cells and through the thickness of the retina, (including its capillary vessels, not shown) before reaching the rods and cones. light is absorbed by the retinal pigment epithelium or the choroid (both of which are opaque).
retina
retinal precursor cells are biological cells that differentiate into the various cell types of the retina during development. in the vertebrate, these retinal cells differentiate into seven cell types, including retinal ganglion cells, amacrine cells, bipolar cells, horizontal cells, rod photoreceptors, cone photoreceptors, and müller glia cells. during embryogenesis, retinal cells originate from the anterior portion of the neural plate termed the eye field. eye field cells with a retinal fate express several transcription factor markers including rx1, pax6, and lhx2. the eye field gives rise to the optic vesicle and then to the optic cup. the retina is generated from the precursor cells within the inner layer of the optic cup, as opposed to the retinal pigment epithelium that originate from the outer layer of the optic cup. in general, the developing retina is organized so that the least-committed precursor cells are located in the periphery of the retina, while the committed cells are located in the center of the retina. the differentiation of retinal precursor cells into the mature cell types found in the retina is coordinated in time and space by factors within the cell as well as factors in the environment of the cell. one example of an intrinsic regulator of this process is the transcription factor ath5. ath5 expression in retinal progenitor cells biases their differentiation into a retinal ganglion cell fate. an example of an environmental factor is the morphogen sonic hedge hog (shh). shh has been shown to repress the differentiation of precursor cells into retinal ganglion cells.
retinal precursor cells