Chapter 7 - Vision

Subdecks (1)

Cards (259)

  • retina
    the receptive surface inside the eye that contains photoreceptors and other neurons
  • transduction
    the conversion of one form of energy to another
  • cornea
    the transparent outer layer of the eye, whose curvature is fixed. bends light rays and is primarily responsible for forming the image on the retina
  • refraction
    the bending of light rays by a change in the density of a medium, such as the cornea and lens of the eye
  • 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
  • accommodation
    the process by which the ciliary muscles adjust the lens to bring nearby objects into focus
  • myopia
    nearsightedness; the inability to focus the retinal image of objects that are far away
  • extraocular muscle
    one of the muscles attached to the eyeball that controls 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 respond to color vision
  • bipolar cell

    an interneuron in the retina that receives 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
  • horizontal cell
    a specialized retinal cell that contacts both photo receptors and bipolar cells
  • amacrine cell
    s 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 involves the rods
  • convergence
    the phenomenon of neural connections in which many cells send signals to a single cell
  • photopic system
    a system in the retina that operates at high levels of light,, shows sensitivity to color, and involves the cones
  • rhodopsin
    the photopigment in rods that responds to light
  • pupil
    the opening, formed by the iris, that allows light to enter the eye
  • iris
    the circular structure of the eye that provides an opening to form the pupil
  • range fractionation
    the means by which sensory systems cover a wide range of intensity values, as each sensory cell specializes in just one part of the overall range of intensities
  • visual field
    the whole area that you can see without moving your head or eyes
  • visual acuity

    sharpness of vision
  • fovea
    the central portion of the retina, which is packed with the highest density of photoreceptors and is the center of our gaze
  • optic disc
    the region of the retina that is devoid of photoreceptors because ganglion cell axons and blood vessels exit the eye there
  • blind spot
    the portion of the visual field from which light falls on the optic disc
  • occipital cortex
    the cortex of the occipital lobe of the brain, corresponding to the visual area of the cortex
  • optic tract
    the axons of retinal ganglion cells after they have passes the optic chiasm. most of these axons termiante in the lateral geniculate nucleus
  • lateral geniculate nucleus
    the part of the thalamus that receives information form the optic tract and sends it to visual areas in the occipital cortex
  • optic radiation
    axons from the lateral geniculate nucleus that terminate in the primary visual areas of the occipital cortex
  • primary visual cortex
    aka V1, striate cortex, or area 17. the region of the occipital cortex where most visual information first arrives
  • binocular
    referring to two-eyed processes
  • extrastriate cortex

    visual cortex outside of the primary visual (striate) cortex
  • topographic organization
    a mapping that preserves the point-to-point correspondence between neighboring parts of space
  • scotoma
    a region of blindness within the visual fields caused by injury to the visual pathway or brain
  • blindsight
    the paradoxical phenomenon whereby within a scotoma, a person cannot consciously perceive visual cues but may still be able to make some visual discrimination
  • receptive field
    the stimulus region and features that affect the activity of a cell in a sensory system
  • on-center bipolar cell
    a retinal bipolar cell that is excited by light in the center of its receptive field