l06 eye and ear Flashcards
done structure of ear and eye and malfunctions of the eye
what is the pupil
opening in the middle of the eye which light passes through
what is the iris
visible coloured ring at the front of the eye adjusts to control the amount of light entering the eye.
what are tear glands
produce tears to clean and lubricate the front of the eye
fluid contains salt and natural antiseptic properties to defend against infection
what is the aqueous and vitreous humours
are the watery, jelly-like fluids that fill the eye
keep the eye in shape and nourish it
what is conjuctivia
thin membrane that protects the cornea
what is the retina
inner lining of the eye, contains light sensistive cells called roads and cones
what is macula
high concentration of photoreceptor cells which detect light and send signals to the brain, interprets them as images
what is the optic nerve
where nerve cells exit the eye
there are no rods or cones there and so this is called the blind spot
what is cilary muscle
enables the lens to change shape for focusing
contracts to stretch the lens making it flatter and thinner
what are the suspensory ligaments
attach the lens to the cilary muscle
what is the lens
focuses light entering the eye
what are the 4 malfunctions of the eye
cataracts, glaucoma, retinopathy, AMD
what are the causes if cataracts
diabetes
exposure to ultraviolet light
taking long term medication like statins
family history
smoking and drinking too much
effects on the eye of cataracts
change in lens, caused by ageing usually and cloidy patches develop in lens
bluurred cloudy or misty vision
colours look pale and less clear
everything have brown or yellow tinge
small patches of less visable vision
double vision
lights uncomfortable to look at, dazzling
causes of retinopathy
complication of diabetes, caused by high blood pressure what damages the retina, well controlled diabetes even sgtill causes blood sugar levels to cause blood vessels to narrow and leak. result in abnormal blood flow to retina, damages cells
effect on eye of retinopathy
can cause blindness if undiagnosed and untreated
possible causes of glaucoma
build up of pressure in eye when fluid from aqueous humour is unable to drain, inctreases pressure and damage optic nerve
can increase risk by age, ethnicity, family history, medical conditions ie diabetes
effects on eye of glaucoma
doesn’t usually cause symptoms to begin with develops slwoly over years and effects peripheral vision first
blurred vision, seeing rainbow coloured circles around some bright lights
if left untreated build up of fluid presses on optic nerve and destroys it eventually causing blindness
causes of age related macular degeneration (AMD)
unknown
linked to smoking, high blood pressure, being overweight and having family history of condition
effects on eye of Age related macular degeneration (AMD)
- doesn’t cause total blindness, make activities hard like reading and recognises faces, loss of central vision
without treatment gets worse and happens gradually
straight lines look wavy of crooked
objects look smaller than normal
colours seem less bright than they used to
seeing things that aren’t there (hallucinations)
what is the eardum structure
thin layer of tissue that receives sound vibrations and transmits them to the middle ear cavity
what is the stapes/ incus/ mallous ear bone structure (stirrup, anvil and hammer)
small bones which amplify the sound waves and transmit the vibrations across the middle of the ear to the cochlea
what is the cochlea ear structure
contains jelly like fluid in a coiled tube that resembles a snails shell, vibrations pass through the fluid and are converted into neural messages and passed onto the brain via the auditory nerve
what is the organ of corti ear structure
located in cochlea and is sometimes called bodys microphone and is lined with rows of hair cells that convert sound vibrations into the nerve impulses
