L06 Eye and Ear Flashcards
Pupil
The opening in the middle of the eye where light passes
Iris
Visible coloured ring
Adjusts to control the amount of light entering through the pupil
Tear glands
Produce tears which clean and lubricate the eye
Contain salt and antibodies to defend against pathogens
Humours
Keep the eye in shape and nourish it
Conjunctiva
Thin membrane that protects the cornea
Cornea
Transparent at the front of the eye
Light rays pass through to the retina
Retina
Inner lining of the eye
Contains light sensitive cells (cones and rods)
Macula
High concentration of photoreceptor cells which detect light and send signals to the brain
Optic nerve
Nerve cells/ impulses exit the eye and go to the brain
No rods and cones = blind spot
Ciliary muscle
Enables lens to change shape for focusing
Lens
Focused light entering the eye
Biological Cause: Glaucoma
A build-up of pressure in the eye when fluid from the aqueous humour is unable to drain properly. This puts pressure on the optic nerve and damaged it.
Factors that increase the risk of glaucoma
Age
Ethnicity
Family History
Medical Conditions like diabetes
Effects of Glaucoma
Develops over many years
Loss of peripheral vision
Blurred vision
Rainbow coloured circles around bright lights
Blindness
What has AMD been linked to?
Smoking, high BP, and obesity
Effects of AMD
Difficulty reading & recognising faces
Straight lines seem crooked
Objects look smaller than usual
Colours seem less bright
Hallucinations
Causes of Cataracts
Diabetes
Exposure to UV light
Taking certain medications such as corticosteroids for a long time
Smoking & drinking
Family history
Effects of Cataracts
Changes in lens resulting in cloudy patches in vision
Colours look pale
Everything has a yellow/orange tinge
Bright lights are dazzling
Double vision
Cause of retinopathy
Diabetes
High blood glucose damages the retina causing blood vessels to narrow and leak
Abnormal blood flow to the retina damages cells
Treatments/monitoring for Glaucoma
Daily eye drops
Regular appointments
Laser treatment to open blocked drainage tube
Surgery to improve to drainage of fluid
Treatments/monitoring for AMD
Stopping smoking
Dietary supplements
Support Services that help with sight loss
Regular scans
Injections into the eye
Photodynamic therapy - light sensitive dye is injected and a laser that activates the dye destroys abnormal blood vessels
Monitoring and treatment for cataracts
Regular eye screening
Stronger glasses
Surgery to replace lens
Monitoring Retinopathy
Monitor & control blood glucose, bp and cholesterol
Diabetic eye screening appointments
Treating retinopathy
Injections of medication into the eye
Laser treatment
Operation to remove scar tissue
Eardrum
Thin layer of tissue
Receives sound vibrations
Transmits them to the middle ear cavity
Stapes/incus/malleus ear bones
Amplify the sound waves
Transmit vibrations across the middle of the ear to the cochlea
Cochlea
Contains jelly-like fluid
Vibrations pass through the fluid and are converted to neural messages
These are passes to the brain via the auditory nerve
Organ of Corti
Located in the cochlea
Lined with rows of hair cells that convert vibrations into nerve impulses
Eustachian Tube
Connects middle ear to the throat
Ensures pressure in the middle ear is equal to pressure outside of the ear
Round Window
Drum-like membrane
Vibrations from the oval window pass through to the cochlea
Auditory Nerve
Bundle of nerve fibres that carry hearing information between the cochlea and the brain
Semi-circular canals and ampullae
Tiny fluid-filled tubes
Help with balance
Lined with cilia
Movement of the cilia are communicated to the brain
A small bone that transmits sound vibrations within the ear
Stapes/incus/malleus
Found in the cochlea and contains rows of hair cells
Organ of Corti
Opening covered by a membrane that allows movement of fluid in the cochlea
Round window
Separated from the external ear by the ear drum
Middle ear
Identify the structures in the middle ear
Semi circular canals
Cochlea
Auditory nerve
Which structure in the ear contains ampullae
Semi circular canals
Effects of deafness
Sound waves do not reach the cochlea
Sound waves are not converted to electrical impulses
Misunderstanding others
Having the TV on loud
May need to learn sign language
Treatment for deafness
Ear drops to dissolve blockages
Syringing to remove blockages
Antibiotics to treat infections
Hearing aids
Explain how sound reaches the brain
Sound enters the outer ear as pressure waves in the air
These vibrations/pressure waves create vibrations of the eardrum
Leads to vibration of the ossicles - which magnify the sound
Vibrations then reach the round window and enter the cochlea
The vibrations are converted into electrical impulses
Electrical impulses travel down the auditory nerve to the brain
Produces liquid to moisten the surface of the eye
Tear gland
Forms a thin protective layer covering the front of the eye and lines the eyelids
Conjunctiva
The lining of the back of the eye that contains cells which are sensitive to light
Retina
State the effects of cataracts
Cloudy patches in vision
Difficulty seeing in dim/bright light
Colours look less faded
Colours have a brown tinge
Double vision
Explain how cataracts effect the functioning of the eye
Cloudy patches in the lens
Colours look pale
Increasing cloudiness eventually leads to sight loss
Explain the cause of glaucoma and the possible effects of left untreated
The build up of pressure in the eye due to the humours not being able to drain properly - Whig damages the optic nerve
When ,eft untreated the peripheral vision reduces
