Vision Flashcards
Refraction
Bending of light rays
Vision Process
- Light is focused through the lens
- The cornea bend light rays and focuses the image on the retina
- Focus is adjusted by changes in the shape of the lens
- Rods and Cones are activated, releasing NT molecules
- Triggers Bipolar Cells that connect with Ganglion Cells
- Axons form the optic nerve that carry information to the brain
- Either the Scotopic or Photopic System is activated
- Scotopic (Rods): Rhodpsin is hit by light it triggers G protein transducin, causing sodium ion channels to close creating a hyperpolarization
Ciliary Muscles
Control the shape of the lens
Pupil
Controls the amount of light that enters the eye
Extraocular Muscles
Extend from the outside of the eyeball.
Fixating still or moving targets require control of these muscles
Bipolar Cells
Located in the retina and receive information from rods and cones and pass the information to retinal ganglion cells.
Ganglion Cells
A class of cells in the retina whose axons form the optic nerve
Horizontal Cells
Contact both the receptor cells and the bipolar cells
Amacrine Cells
Contact both the bipolar cells and the ganglion cells
Especially significant in inhibitory interactions within the retina
Rods, Cones, Bipolar Cells, and Horizontal Cells generate…
Local potentials
Ganglion Cells generate…
Action potentials
Scotopic System
Operates with rods and works in dim light
Photopic System
Operates at high levels of light, shows sensitivity to color and involves the cones
Rods
Work in dim light
Contain Rhodopsin
Concentrated in the periphery of the retina
Cones
Work to distinguish colors
Contain Opsin
Concentrated in the fovea