Eyes and Ears Flashcards
cornea
light enters the eye through a transparent window called the cornea
pupil
opening permitting light to pass through
iris
regulates amount of light entering the eye because it controls size of pupil
lens
located behind cornea, focuses light rays falling on the retina, made of soft tissue
visual accommodation
occurs when the curvature of the lens adjusts to alter the focus
retina
adjusted light is then focused on the back of the eye
cones
detect color
fovea
light falls directly onto densest cluster of cones
rods
detect black white and gray
bipolar cells
from rods to cones light travels as neural signals to bipolar cells
activate ganglion cells
ganglion cells
converge to form optic nerve
blind spot
optic nerves form inside half of each eye cross over then project to the opposite half of the brain
pinna
outer ear
auditory canal
vibrations enter and go to the eardrum
ossicles
transmit sounds from air to cochlea
cochlea
coiled, bony fluid filled tube through which sound waves trigger neural impulses
basilar membrane
moves with incoming soundwaves and is essential to hearing
auditory nerve
nerve goes to thalamus
thalamus
goes to temporal lobe
optic nerve
ganglion cells converge to form this
Optic chiasm
Optic nerves cross over and project to opposite half of brain.
(recall this was NOT severed in the split brain patients)
Thalamus
From optic chiasm, information processed through here
Occipital Lobe (Visual cortex)
From thalamus, information sent to occipital lobe
Theories of Vision
Young-Helmholtz Trichromatic Theory
and
Opponent-process theory (after images)
Young- Helmholtz Trichromatic theory
How many primary colors? red green blue
What is the theory- Cones in eye are tuned to detect red green or blue light
Opponent-process theory (after images)
Color is processed in opponent pairs
sensory interaction (visual capture)
when you perceive conflict between/amongst sense, vision usually dominates.
Eardrum
Separates outer ear from middle ear
Oval window
Connective tissue at the end of middle ear and beginning of inner ear
(inside the chochlea)
Organ of Corti
Allows for transduction of sound vibrations into neural signs
(inside the basilar)
Membrane: hair cells
trigger impulses sent to auditory nerve
Theories of Audition
Place theory
frequency-matching theory
volley principle
sound localization
(look at models)
Place theory
links pitch to where cochlea’s membrane is stimulated
(see visual)
Frequency-matching theory
rate of nerve impulses traveling up auditory nerve matches frequency of tone
Volley principle
If a sound is too high (close to 20,000 Hz) or low (closer to 20 Hz)
Neurons work together and fire in stages at high or low frequencies
Sound Localization
sound waves hit one ear sooner and more intensely than other allowing us to locate sources
(see visual)
Nearsightedness
Occurs when shape of eye causes light rays to refract focusing in front of retina
Farsightedness
Light aimed behind retina
Color-Blindness
(three types)
- red-green
- blue-yellow
- Complete colorblindness (monochromacy)
Conductive hearing loss
Damage to mechanical system conducting sound waves to cochlea
Conductive hearing loss
Damage to mechanical system conducting sound waves to cochlea
Sensorineural hearing loss
damage to hair cells of cochlea
