| A | B |
|---|
| Visible spectrum | "The part or range of wavelengths of electromagnetic radiation that is visible to the human eye." |
| Cornea | "the clear part of the eye that lies in front of the iris and is part of the eye's protective covering." |
| Pupil | "the opening in the center of the eye that controls how much light is let into the eye." |
| Iris | "the colored portion of the eye that controls how much light enters the pupil." |
| Lens | "the portion of the eye that changes shape in order to focus the visual image onto the retina." |
| Retina | "the layer of cells at the back of the eye which contain photoreceptors and additional neurons, where transduction of light waves into nerve signals takes place." |
| Accommodation | "the lens of the eye changes shape in response to changing external conditions, so that the object remains in focus." |
| Presbyopia | "A progressive reduction in the eye's ability to focus, associated with aging, with difficulty in reading at the normal distance. This is due to an age-related loss of elasticity of the lens." |
| Myopic | "Unable to clearly see things that are at a distance." |
| Hyperopic | "A condition where vision is better for seeing distant things than for seeing things that are nearby, because visual images come to a focus behind the retina. Also called farsightedness." |
| Cones | "the visual receptors in the retina that are responsible for color vision, but are less useful for seeing in conditions of low light." |
| Transduction | "The conversion of sensory stimuli, such as sound waves, into a form that can be processed by the sense receptors." |
| Bipolar cells | "cells in the visual system that connect the photoreceptors (rods and cones) to the ganglion cells." |
| Ganglion cells | "cells in the retina that receive visual information from the photoreceptors via the bipolar cells, and pass the information on to the brain. The axons of the ganglion cells form the optic nerve, which passes out the back of the eye." |
| Optic nerve | "the cranial nerve that carries the visual impulse out the back of the eye and into the brain for further processing." |
| Fovea | "a depression near the center of the retina that is densely packed with cones. The fovea is where vision is most acute." |
| Dark adaptation | "The changes that occur in the eye to permit vision when moving from light to darkness." |
| Light adaptation | "The changes that occur in the eye to permit vision when moving from darkness to light." |
| Blind spot | "An area or direction in which a person's vision is obscured." |
| Optic nerve | "the cranial nerve that carries the visual impulse out the back of the eye and into the brain for further processing." |
| Ganglion cells | "cells in the retina that receive visual information from the photoreceptors via the bipolar cells, and pass the information on to the brain. The axons of the ganglion cells form the optic nerve, which passes out the back of the eye." |
| Thalamus | "the portion of the brain whose primary function is to relay information from sensory systems (such as the visual system) to the cerebral cortex." |
| trichromatic (Young-Helmholtz) theory | "A theory of color vision in which three types of color receptors produce the three basic colors of red, green, or blue." |
| Opponent process theory | "a theory of color vision in which colors are produced through the combined actions of" |
| Pitch (frequency) | "The frequency of sound waves, which translates into the highness or lowness of a sound." |
| Loudness (amplitude) | "The height of the sound waves generated by an auditory stimulus" |
| Timbre (complexity) | "The quality of sound that is the result of the mixture of wavelengths in the sound" |
| Pitch (frequency) | "The frequency of sound waves, which translates into the highness or lowness of a sound." |
| Pinna | "the visible outer portion of the ear." |
| Auditory canal | "Either of the passages in the outer ear from the auricle to the tympanic membrane." |
| Eardrum | "Another term for the tympanic membrane." |
| Tympanic | "Related to the eardrum (as in, tympanic membrane)." |
| Malleus (hammer) | "One of the three ossicles, or small bones in the middle ear." |
| Incus (anvil) | "one of the three ossicles, or the bones of the middle ear.)" |
| Stapes (stirrup) | "one of the three ossicles, or bones of the middle ear." |
| Ossicles | "the three small bones of the middle ear." |
| Window | "Membrane that separates the middle and inner ear." |
| Cochlea | "The snail-shaped, fluid-filled organ in the inner ear which contains the basilar membrane." |
| Basilar membrane | "The membrane that runs along the length of the cochlea in the inner ear. The vibration of the basilar membrane is what allows us to perceive differences in pitch, particularly with higher-pitched sounds." |
| Transduction | "The conversion of sensory stimuli, such as sound waves, into a form that can be processed by the sense receptors." |
| Auditory cortex | "The portion of the cerebral cortex that is responsible for processing auditory information. It is located in the temporal lobes of the cerebral cortex." |
| Place theory | "A theory of how the perception of the pitch of a sound depends upon the level or part of the basilar membrane of the cochlea which is set into vibration by the sound waves." |
| Frequency theory | "A theory that sound is hear when pulses travel up the auditory nerve, and carry the information about sound to the brain for processing; and that the rate of this pulse exactly matches the frequency of whatever tone is heard." |
