9: VISION Flashcards
STIMULUS of VISUAL SYSTEM
LIGHT
narrow band on light spectrum of electromagnetic radiation w wavelength btwn 380-760 mm
VISIBLE LIGHT TO HUMANS
Bees can detect ____ on the spectrum of electromagnetic radiation
UV RADIATION
3 DIMENSIONS THAT DETERMINE PERCEIVED COLOUR OF LIGHT
- HUE
- SATURATION
- BRIGHTNESS
dimension of light determined by WAVELENGTH
HUE
dimension of light that = relative PURITY of light
SATURATION
dimension of light that = INTENSITY of light
BRIGHTNESS
relative constant appearance of colours of objects viewed under varying lighting conditions
COLORU CONSTANCY
SHORTER wavelengths = ___ freq
LONGER wavelengths = ___ freq
HIGHER; LOWER
specialized neuron that detects participate category of physical events
SENSORY RECEPTORS
neural tissue + photoreceptive cells located on inner surface of back of eye
RETINA
opaque white outer layer of most of eye that does NOT let light into eye
SCLERA
transparent outer layer at front of eye
CORNEA
opening in IRIS that regulates amt of light that enters eye (based on its size)
PUPIL
pigmented ring of muscles behind CORNEA
IRIS
series of transparent/onionlike layers behind IRIS that changes shape from contractions of CILIARY MUSCLES that permit eye to focus images of near/distant objects on RETINA
LENS
RETINA + OPTIC NERVES = in ___ (CNS or PNS)
CNS
changes in thickness of LENS that focuses images of near/distant objects on RETINA
ACCOMMODATION
receptor cells of RETINA that transduce PHOTIC ENERGY into ELECTRICAL POTENTIALS
PHOTORECEPTORS
2 TYPES OF PHOTORECEPTOR CELLS
- RODS
- CONES
- most prevalent in CENTRAL RETINA (found in FOVEA)
- sensitive to MODERATE-HIGH levels of light
- for DAYTIME/COLOUR vision
- provide info abt HUE
- provide EXCELLENT acuity
RODS
- most prevalent in PERIPHERAL RETINA (NOT in FOVEA)
- sensitive to LOW levels of light
- for NIGHT vision
- provide only MONOCHROMATIC info (B+W)
- provide POOR acuity
CONES
RODS + CONES contain ___ that provide input to ___ + ___ CELLS
PHOTOPIGMENTS; BIPOLAR + HORIZONTAL
protein dye bonded to RETINAL (substance derived from vitamin A) which = responsible for TRANSDUCTION of visual info
PHOTOPIGMENTS
PHOTORECEPTORS + BIPOLAR CELLS ___ (do/do not) produce ACTION POTENTIALS
DO NOT
idea that a bunch of cells at back of eye converge into smaller + smaller number of cells that process what we’re looking at
CONVERGENCE
2 MAIN CELLULAR LAYERS OF RETINA
- PHOTORECEPTIVE LAYER
- BIPOLAR LAYER
- GANGLION CELL LAYER
central region of RETINA w GREATEST VISUAL ACUITY
FOVEA
how well a person can FOCUS on an object
VISUAL ACUITY
Which type of PHOTORECEPTOR = found in FOVEA
CONES
point where fibres of GANGLION CELLS that form OPTIC NERVE exit RETINA
OPTIC DISK
what part of RETINA = responsible for BLINDSPOT?
OPTIC DISK
cells in MIDDLE layer of RETINA that convey info from PHOTORECEPTORS to GANGLION CELLS
BIPOLAR CELLS
cells that:
- receive info from BIPOLAR CELLS
- their axons give rise to OPTIC NERVE
- carry visual info to rest of brain
GANGLION CELLS
cells that interconnect adjacent PHOTORECEPTORS + outer processes of BIPOLAR CELLS
HORIZONTAL CELLS
cells that interconnect adjacent GANGLION CELLS + inner processes of BIPOLAR CELLS
AMACRINE CELLS
part of visual field that individuals neuron sees
RECEPTIVE FIELD
RECEPTIVE FIELD = portion of visual field in which presentation of visual stimuli will produce an ___ in ___ ___ of particular neuron
ALTERATION; FIRING RATE