Across
- 3. The retina contains two types of photoreceptors that have an outer segment, both composed of ____ disks containing light-sensitive photopigment.
- 7. The central area of the fovea that is totally rod-free is called the ______.
- 8. The center-surround arrangement of ganglion cell receptive fields makes these neurons particularly sensitive to luminance contrast and relatively insensitive to the overall level of ______.
- 9. Photopigment in rods.
- 10. The restoration of retinal to a form capable of signaling photon capture is a complex process known as the ____ cycle.
- 11. When ___ binds, the ability of activated rhodopsin to activated transducin in blocked.
- 12. In the dark, photoreceptors are relatively _____.
- 13. Dynamic changes in the refractive power of the lens
- 16. Changes in opsin lead to the activation of an intracellular messenger called ____, which activates a phosphodiesterase that hydrolyzes cGMP.
Down
- 1. In the dark, cations flow into the outer segment through membrane channels that are gated by ____in a fashion similar to that of other second messenger systems.
- 2. The processes of ___ cells enable lateral interactions between photoreceptors and bipolar cells that are thought to maintain the visual system's sensitivity to contrast, over a wide range of light intensities.
- 4. The process by which light is converted into electrical signals in the brain
- 5. Rods don't contribute to ____ vision because their response to light saturates.
- 6. _____ release from photoreceptor terminals has a depolarizing effect on horizontal cells.
- 14. ____ vision occurs in levels of light such as twilight, where both rods and cones contribute.
- 15. The reduction in ___ release from the horizontal cells has a depolarizing effect on the membrane potential of the central photoreceptor.