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80 terms

anatomy eye an ear

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special senses
what allows the body to react to the environment
sight taste smell hearing balance maintenance
special senses are
eye
organ that controls sight
recieves light rays and transmits impluses from rays to optic nerve
what does the eye do
eyelids and lashes bony socket
what protects the eye
lacrimal glands
what produces tears and miostens and cleanses the eye
conjunctiva (provides additional protection and lubrication
a mucous membrane that lines the eyelids and covers the front of the eye
3layers
how many layers are there to the eye
sclera white of the eye
outermost layer of the eye tough connective tisssue maintains shape of the eye
extrinsic muscles (attached to outside of sclera
responsible for moving eye within socket
cornea
circular transparent part of the front of the sclera
allows light rays to enter eye
what does the cornea do
choroid coat (interlaced with blood vessels that nourish the eye
middle layer of the eye
retina (layers of nerve cells)
inner most layer of the eye
transmits light impulses to optic nerve
what does the retina do
cones and rods
what are two special cells of the retina
cones
sensitive to color used mostly for vision in the light
fovea centralis (back surface of the retina) (sharpest vision here)
where are cones located
rods
vision in the dark
iris
colored part of the eye located behind the cornea on the front of the choroid coat
pupil
opening in center of iris
2muscles
iris contains what to control size and regulate the amount of light entering the eye
lens
circular structure located behind pupil and suspended in position by ligaments
refracts (bends) the light rays so the rays focus on the retina
what does the lens do
aqueous humor (clear watery fluid)
what fills the space between the cornea and iris
helps maintain forward curvature of eyeball and refracts light rays
what does the aqueous humor do
vitreous humor
fill area behind lens helps maintain shape of eyeball and refracts lightrays
cornes aqueous humor pupil lens vtreous humor
when light rays enter the eye what parts do they pass throuogh
rods and cones
light rays are picked up in the retina by
nerve impluses and transmitted by optic nerve to optical lobe of the cerebrum
cones and rods change light rays to what
lazy eye early childhood
what is amblyopia
abnormal shape or curvature of the cornea light rays focus on multiple areas of the retina
astigmatism
cataract (sight restored by surgical removal of lens)
normally clear lens becomes cloudy or opaque (aging)
conjuntivitis (pink eye)
inflamation of the conjuncitiva (bacterium or virus)
Glaucoma
increased intraocular pressusre caused by excess aqueous humor (after 40) leads to blindness
hyperopia
farsightedness light rays not refracted sharply enouogh and image foucues behind retina
marcula
center and most sensitive section of the retina
macular degeneration (age related)most common type dry macul degeneration
disease of the marcula caused by damage to the blood vessels that nouorish the retina
dry macul degeneration
fatty deposits decrease blood supply to retina
wet macul degeneration
abnormal growth of blood vesssels leak blood and fluids that damage retina
myopia (corrected by concave lenes or by surgical procedure called radial keratotomy small incision made to flatten cornea
nearsightedness occurs when light rays are refracted too sharply and the image focuces in front of the retina
presbyopia normal ageing corrective lenes
farsightedness caused by loss of lens elasticity light rays focus behind the retina
strabismus cover good eye corrective lenses or surgery on the muscles that move the eye
disorder in which the eyes do not nove or focus together
ear transmits impluses from aound waves to auditory nerve (vestibulocochlear)
organ that controls hearing and balance
3main sections outer middle an inner
how many sections is the ear divided into and what are they callled
pinna or auricle pinna is elastic cartilage covered by skin
what is the outer part of the ear called and what is it
a canal or tube called the auditory canal (external auditory meatus)
pinna or auricle leads to what
a wax that protects the ear
what is the cerumen
eardrum or tympanic membrane
sound waves travel through the auditory canal untill they reach the
tympanic membrane it vibrates when sound waves hit it and transmits the sound waves to middle ear
what seperates the outer ear from the inner ear and what does it do
a small space or cavity in the temporal bone contains 3 small bones called ossicles
what is the middle ear and what does it contain
malleus incus and the stapes they are connected and transmit sound waves from the tympanic membrane to the inner ear
name the 3 small bones of the middle ear and what they do
eustachian tube
the middle ear is connected to the pharynx or throat by what
allows air to enter middle ear and helps equalize air pressure on both sides of the tympanic membrane
what does the eustachian tube do
inner ear
what is the most complex portion of the ear
a membrane called the oval window
what seperates the inner ear from the middle ear
vestibule acts as an entrance to the two other parts of the inner ear
what is the frist section of the inner ear and what does it so
cochlea delicate hairlike cells which compose the organ of corti
shaped like a snail's shell and what does it contain
a receptor of sound waves it transmits the impluses from sound waves to the auditory nerve where they are interperted as hearing
what is the organ of corti and what does it do
auditory nerve
what carries the impluses to the temporal lobe of the cerebrum
semicircular canals
located in inner ear contain liquid and delicate hairlike cells theat bend when liquid moves with head and body movements
sense of balance and equilibrium
impluses sent from semicucular canals to the cerebellum of the brain help to maintain what
conductive and sensory
what are two kinds of hearing loss
conductive hearing loss treatment surgery or hearing aids
sound waves are not conducted to inner ear caused by wax forgein body otosclerosis or ruptured tympanic membrane
sensory hearing loss usually cannot be corrected but cochlear implants can improve hearing loss
damage to inner ear or auditory nerve
meniere's disease
collection of fluid in the labyrinth of the inner ear and a degeneration of the hair cells in the cochlea vestibule symptoms vertigo tinnitus naussea vomiting loss of balance
otitis externa
inflamation of the external auditory canal caused by pathogenic organism such as bacterium or viris swimmer's ear
otitis media myringotomy incicion of tsypanic membrane tubes insserted to relieve pressure and allow fluid to drain
inflamation or infection of middle ear caused by bacterium or viris frently follows sore throat (organisms can enter middle ear through eustachian tube
otosclerosis surgical removal of sstapes and insertion of artifical stapes corrects condition
stapes become immoble causing conductive hearing loss symptom gradule hearing loss tinnitus at times vertigo
a mass of muscle tissue with porojections called papillae
what is the tongue
contain taste buds that are simulated by foods moistened by saliva
what are papillae
sweet and salty (tip of tongue) sour (side of tongue) bitter ( back of tongue)
what are the 4 main tastes and where are they located
smell
what is taste influenced by
nose
what is the organ of smell
olfactory receptors located in the upper part of nasal cavity
what makes the sense of smell possible
6000
how many different smells can the nose detect
yes
is the sense of smell more sensitive than taste
located throughout the body
general sense receptors for pressure heat cold touch and pain
each receptor recieves only one type of sense
how many sense's does a receptor detect
yes
does the skin have special receptors for both heat and cold