LO6: Sensory Systems Flashcards
(34 cards)
What is the pupil?
Opening in the middle of the eye through which light passes
What is the iris?
Visible coloured ring at the front of the eye, contracts and adjusts to control amount of light entering the eye through the pupil
What is the tear glands?
Produce tears to clean and lubricate front of the eye, fluid contains salt and natural antiseptic properties to protect against infection
What is the aqueous and vitreous humour?
Watery jelly like fluids that fill the eye in shape and nourish it
What is the conjunctiva?
Thin membrane that protects the cornea
What is the cornea?
Front of the eye and is transparent, protects the eye, light rays pass through the cornea to the retina
What is the retina?
Inner lining of the eye contains light sensitive cells called rods and cones
What is the macula?
Very high concentration of photoreceptor cells, detect light and send signals to the brain which interprets them as images
What is the optic nerve?
Where nerve cells exit the eye, no rods or cones, called the blind spot
What are the ciliary muscles?
Enables lens to change shape for focusing, contracts to stretch lens, makes it flatter and thinner
What are the dispensary ligaments?
Attach lens to ciliary muscles
What is the lens?
Focuses light entering the eye through
What is the biological explanation for glaucoma?
Build of pressure in the eye where fluid from the aqueous humour is unable to drain properly, increases pressure and damages the optic nerve
What are the possible causes of glaucoma?
Age: older you are more common it is
Ethnicity: people of African, Caribbean and Asian origin are at higher risk
Family history: more likely to develop if parent of sibling has it
Other medical conditions: glaucoma is more common for those with diabetes
What are the symptoms/effects of glaucoma?
Doesn’t usually cause any symptoms to begin with, develops slowly over many years and effects peripheral vision first
May only be found during routine eye tests
Blurred vision, rainbow coloured circles around bright lights
If left untreated build up of fluid presses on optic nerve destroying it and causing blindness
Treatments for glaucoma?
Daily eye drops administered by individual
Regular appointments to monitor condition, check eye drops work
Laser treatment to open up blocked drainage tubes, reduce fluid production in the eye
What is the biological cause of AMD?
Obstruction and damage to the macula causing the central vision to worsen over time
What are the possible causes of AMD?
Exact cause is unknown
Linked to smoking, high blood pressure, being overweight, family history of the condtion
What are the symptoms/ effects of AMD?
Make everyday activites such as reading and recognising peoples faces very difficult
Seeing straight lines as wavy or crooked
Objects look smaller than normal
Treatments of dry AMD
No treatment to cure the condition
Stop smoking
Diet with plenty of leafy greens to slow progression
Treatments of wet AMD
Regular scans to monitor
Injections in the eye
Photodynamic therapy (laser treatment) activates dye to destroy abnormal blood vessels
What is the biological cause of cataracts?
Clouding of the eyes natural lens, caused by breakdown and clumping of proteins with the lens
Possible causes of cataracts
Diabetes
Exposure to UV lights in sunlight
Smoking and drinking too much alcohol
Symptoms/ effects of cataracts
Cloudy patches developing in the lens
Cloudy/ misty vision
May have double vision
