Upgrade to remove ads
Terms in this set (48)
transparent outer layer of the eye with a fixed curvature. it bends light rays and is primarily responsible for focusing light into an image on the retina.
structure in the eye rostral to the cornea that helps focus light onto the retina. in fish/amphibians/reptiles, it moves in and out like a camera's to focus light. in mammals and birds, the ciliary muscles change its shape to focus light.
bending of light rays caused when a ray of light encounters a medium with a different density. this happens when light hits the cornea and the lens of the eye.
one of the muscles that controls the shape of the lens inside the eye, focusing an image on the retina
the process of focusing by the ciliary muscles and the lens to form a sharp image on the retina. as mammals age, their lenses become less elastic, making it more difficult to focus on objects that are near - humans correct this problem with reading glasses.
the opening, formed by the iris, that allows light to enter the eye. size of the opening controls how much light can enter.
the circular structure of the eye that provides an opening to form the pupil
three pairs of muscles that extend from the outside of the eyeball to the bony socket of the eye. controls eye position and movement, allows eye to focus on still or moving objects.
receptive surface inside the back of the eye containing layers of photoreceptors, bipolar cells, and ganglion cells. projects to the brain in a topographic fashion.
neural cells in the retina that respond to light. there are two types: rods and cones.
class of photoreceptors in the retina that are most active at low levels of light. provide high sensitivity with limited acuity.
class of photoreceptors in the retina that are responsible for color vision. provide low sensitivity with high acuity.
class of interneurons of the retina that receive information from rods and cones and pass the information to retinal ganglion cells
class of cells in the retina whose axons form the optic nerve. the only type of retinal cell that produces action potentials (the others only generate graded local potentials).
cranial nerve II, the collection of ganglion cell axons that extend from the retina to the optic chiasm
specialized retinal cells important in lateral interactions - they contact both the photoreceptors and the bipolar cells
specialized retinal cells important in lateral interactions - they contact the bipolar cells and ganglion cells and are important in inhibitory interactions within the retina
system in the retina that operates at low levels of light and involves the rods. a lot of information processing occurs here.
system in the retina that operates at high levels of light, shows sensitivity to color, and involves the cones. some information processing occurs here.
photopigment used by rods that responds to light
one of the components, along with opsin, of photopigments in the retina
one of the components, along with retinaldehyde, of photopigments in the retina
the handling of different light intensities by different receptors - some with low thresholds (rods) and some with high thresholds (cones)
the progressive loss of receptor sensitivity as stimulation is maintained - each photoreceptor adjusts its sensitivity to match the ambient illumination. this shows that the visual system is concerned with changes in brightness, not with the absolute level of illumination. main reason we can see over such wide ranges of light.
controlled by: regulation of intracellular calcium concentrations and recombination of retinaldehyde and opsin.
the whole area that you can see without moving your head or eyes. the right visual field, which falls on parts of both retinas, gets projected to the left cerebral hemisphere (and vice versa). however, not everything that the right eye sees gets projected to the left side - since the right eye can see part of the left visual field.
sharpness of vision. it is especially fine in the center of the visual field and falls off rapidly at the peripheries.
central portion of the retina containing a dense concentration of cones. visual acuity is greatest here because light can reach the cones without having to pass through blood vessels and other layers of cells.
region of the retina nasal to the fovea where ganglion cell axons and blood vessels exit the eyeball. no photoreceptors here, so it creates a blind spot (we usually don't notice it though)
portion of the visual field from which light falls on the optic disc, which has no photoreceptors - the light cannot be seen
the phenomenon by which interconnected neurons inhibit their neighbors, producing contrast at the edges of visual regions. this is an example of how the visual system doesn't engage in simple reporting of the physical properties of light, but our experience of light versus dark is created by a combination of responses by the brain to various stimuli.
the point at which the two optic nerves from each eye meet and cross to form optic tracts
the axons of retinal ganglion cells after they have passed the optic chiasm; most terminate in the lateral geniculate nucleus of the thalamus
lateral geniculate nucleus
part of the thalamus that receives information from the optic tract and send it to visual areas in the occipital cortex
axons from the lateral geniculate nucleus that terminate in the primary visual areas of the occipital cortex
primary visual cortex
aka striate cortex or area 17. the region of the occipital cortex where most visual information first arrives.
large region of the cortex covering much of the posterior part of each cerebral hemisphere, specialized for visual processing
visual cortex outside of the primary visual cortex
the stimulus region and features that affect the activity of a cell in a sensory system
on-center bipolar cells
retinal bipolar cells that are excited by light in the center of their receptive fields - this is determined by the type of glutamate receptors they have. ex: turning on a light in the center of this cell's receptive field would excite it because it would receive less glutamate from the photoreceptors
off-center bipolar cells
retinal bipolar cells that are inhibited by light in the center of their receptive fields - this is determined by the type of glutamate receptors they have. ex: turning off a light in the center of this cell's receptive field would excite the cell because it receives more glutamate from the photoreceptors
on-center ganglion cells
retinal ganglion cells that are activated when light is presented to the center, rather than the periphery, of the cells' receptive fields. ex: when a light is turned on, photoreceptors hyperpolarize, on-center bipolar cells excite, and these cells excite.
off-center ganglion cells
retinal ganglion cells that are activated when light is presented to the periphery, rather than the center, of the cells' receptive fields. ex: when a light is turned off, photoreceptors excite, off-center bipolar cells excite, and these cells excite.
concentric receptive field (for a bipolar or ganglion cell) in which the center excites the cell of interest while the surround inhibits it
concentric receptive field (for a bipolar or ganglion cell) in which the center inhibits the cell of interest while the surround excites it
referring to the small cells in the dorsal layers (3-6) of the lateral geniculate nucleus. have relatively small receptive fields and receive input that traces back to single cones, so they can discriminate wavelengths
referring to the large cells in the ventral layers (1-2) of the lateral geniculate nucleus. have relatively large receptive fields, do show differential wavelength responses, and therefore not involved in color discrimination
simple cortical cell
aka bar detector or edge detector. a cell in the visual cortex that responds best to an edge or a bar that has a particular width, as well as a particular orientation and location in the visual field
complex cortical cell
a cell in the visual cortex that responds best to a bar of a particular size and orientation anywhere within a particular area of the visual field
THIS SET IS OFTEN IN FOLDERS WITH...
Taste and Smell
YOU MIGHT ALSO LIKE...
Biological Psychology Chapter 10 - Vision
BioPsych Test 2 - Visual System
OTHER SETS BY THIS CREATOR
Muscles of the Wrist and Forearm
Muscles of the Lower Extremities
Muscles of the Upper Extremities and Back
Muscles of Respiration and Pelvis