Chapter 4 - Sensation and Perception Flashcards
Sensation
The stimulation of sense organs.
Perception
The selection, organization, and interpretation of sensory input.
Light
A form of electromagnetic radiation that travels as a wave as at the speed of light.
Amplitude
Height
Wavelength
Distance
Amplitude affects the perception of ___, while wavelength affects the perception of ____.
Brightness, color.
Purity
How varied the mix of light is.
Purity influences the variation of the ____, or richness of color.
Saturation
What two main purposes do the eyes serve?
- They channel light to the retina.
2. They house the retina.
Cornea
A transparent “window” through which light enters the eye.
The ____ and the crystalline ____ form an upside down image of objects on the retina and adjust the focus of the image.
Cornea, lens
Lens
A transparent eye structure that focuses the light rays falling on the retina.
Accommodation
The curvature of the lens adjusts to alter visual focus.
A number of common visual problems are caused by focusing problems or defects in the ____.
Lens
Nearsightedness
Close objects are seen clearly but distant objects appear blurry because the focus of the light from distant objects falls a little short of the retina.
Occurs when the cornea or lens bends light too much or the eyeball is too long.
Farsightedness
Distant objects are seen clearly but close objects appear blurry because the focus of the light from close objects falls behind the retina.
Typically occurs when the eyeball is too short.
Cataract
A lens that is clouded. Occurs mainly in older persons, affecting 3 out of 4 people over the age of 65.
Iris
The colored ring of muscle surrounding the pupil, or black center of the eye.
Pupil
The opening in the center of the iris that help regulates the amount of light passing into the rear chamber of the eye.
Retina
The neural tissue lining the inside back surface of the eye;it absorbs light, processes images, and sends visual information to the brain.
The ____ is the brain’s envoy into the eye.
Retina
Optic disk
A hole in the retina.
Since the optic disk is a hole in the retina, you cannot see the part of the image that falls on it. It is therefor known as the ____ blind spot.
Blind spot
_____ outnumber _______ blank. Humans have 100-125 million _______ but only 5-6.4 million _______.
Rods, cones, rods, cones.
Cones
Specialized visual receptors that play a key role in daylight vision and color vision.
Cones provide better visual acuity, sharpness and precise detail.
Concentrated most heavily in the center of the retina and fall off in density toward its sides.
Fovea
A tiny spot in the center of the retina that contains only cones; visual acuity is greatest at this spot.
Rods
Specialized visual receptors that play a key role in night vision and peripheral vision.
The density of the rods is greatest just outside of the fovea and gradually decreases toward the periphery of the retina.
Dark adaptation
The process in which the eyes become more sensitive to light in low illumination.
Light adaptation
The process in which the eyes become less sensitive to light in high illumination.
Optic nerve
A collection of axons that connect the eye with the brain.