The Visual System Extends from the Eye to the Brain Flashcards
Retina
The receptive surface inside the eye that contains photoreceptors and other neurons.
Transduction
The conversion of one form of energy to another, as converting light into neuronal activity.
Cornea
The transparent outer layer of the eye, whose curvature is fixed. The cornea bends light rays and is primarily responsible for forming the image on the retina.
Figure 7.1
Structures of the Human Eye
Refraction
The bending of light rays by a change in the density of a medium, such as the cornea and the lens of the eyes.
Lens
A structure in the eye that helps focus an image on the retina.
Ciliary Muscle
One of the muscles that control the shape of the lens inside the eye, focusing an image on the retina.
Accomodation
The process by which the ciliary muscles adjust the lens to focus a sharp image on the retina.
Myopia
Nearsightedness; the inability to focus the retinal image of objects that are far away.
Figure 7.2
Focusing Images on the Retina
Extraocular Muscle
One of the muscles attached to the eyeball that control its position and movements.
Photoreceptor
A neural cell in the retina that responds to light.
Rod
A photoreceptor cell in the retina that is most active at low levels of light.
Cone
Any of several classes of photoreceptor cells in the retina that are responsible for color vision.
Figure 7.3
A.
Anatomy of the Retina
Figure 7.3
B.
Anatomy of the Retina
Bipolar Cell
An interneuron in the retina that recieves information from rods and cones and passes the information to retinal ganglion cells.
Ganglion Cell
Any of a class of cells in the retina whose axons form the optic nerve.
Optic Nerve
Cranial nerve II; the collection of ganglion cell axons that extend from the retina to the brain.
Horizontal Cell
A specialized retinal cell that contacts both receptor cells and bipolar cells.
Amacrine Cell
A specialized retinal cell that contacts both bipolar cells and ganglion cells, and is especially significant in inhibitory interactions within the retina.
Scotopic System
A system in the retina that operates at low levels of light and involes rods.