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Sense Organs LC Biol
Term | Definition |
---|---|
Receptor | Cells sensitive to stimulus, usually concentrated in a sense organ |
Sclera | .outer layer of eye .opaque .protective |
Choroid | .Middle eye layer .Black with melanin .prevents internal rflection .contains blood vessels |
Aqueous Humour | .watery filling in front of lens .gives front of eye shape |
Vitreous Humour | .jelly filling behind lens .shapes back of eye |
Cornea | |
Outer transparent part of sclera at the front of the eye | |
Retina | Inner layer Light sensitive Image forms here Contains rods + cones |
Lens | Transparent convex jelly Focuses light rays onto retina |
Ciliary muscle | Accommodation Changes lens shape to focus Near / far objects |
Suspensory ligaments | Hold lens in place |
Iris | Coloured muscle Adjusts pupil size by reflex Control amount light entering |
Pupil | Hole in iris Lets light in |
Blind spot | Part of retina with no rods or cones No vision |
Optic nerve | Sensory nerve Brings images from retina to brain |
Eye Muscle | Anchors eye ball in socket Eye movements |
Rods | Light sensitive cells in retina Most numerous + everywhere Dim light Black n white |
Cones | Least Concentrated in the fovea Bright light Colour |
External auditory canal | Links pinna to inner ear Carries sound waves to eardrum |
Pinna | Funnels sound waves into inner ear |
Eardrum | Tympanic membrane Vibrates with sound waves Passes on to ossicles |
Eustachian tube | Links middle ear to pharynx Equalises pressure either side of eardrum Prevents eardrum bursting |