Sensory Systems Flashcards by Chloe Rhodes

Pupil

The opening in the middle of the eye where light passes

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Iris

Visible coloured ring
Adjusts to control the amount of light entering through the pupil

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Tear glands

Produce tears which clean and lubricate the eye
Contain salt and antibodies to defend against pathogens

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Humours

Keep the eye in shape and nourish it

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Conjunctiva

Thin membrane that protects the cornea

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Cornea

Transparent at the front of the eye
Light rays pass through to the retina

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Retina

Inner lining of the eye
Contains light sensitive cells (cones and rods)

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Macula

High concentration of photoreceptor cells which detect light and send signals to the brain

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Optic nerve

Nerve cells/ impulses exit the eye and go to the brain
No rods and cones = blind spot

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Ciliary muscle

Enables lens to change shape for focusing

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Lens

Focused light entering the eye

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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.

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Factors that increase the risk of glaucoma

Age
Ethnicity
Family History
Medical Conditions like diabetes

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Effects of Glaucoma

Develops over many years
Loss of peripheral vision
Blurred vision
Rainbow coloured circles around bright lights
Blindness

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What has AMD been linked to?

Smoking, high BP, and obesity

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Effects of AMD

Difficulty reading & recognising faces
Straight lines seem crooked
Objects look smaller than usual
Colours seem less bright
Hallucinations

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Causes of Cataracts

Diabetes
Exposure to UV light
Taking certain medications such as corticosteroids for a long time
Smoking & drinking
Family history

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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

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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