Sense Organs Flashcards
Aqueous Humour
Watery fluid that fills the front Chamber of the eye
Conjunctiva
Thin Membrane protecting the cornea
Cornea
Transparent layer that refracts light
Pupil
Circular opening for directing light into lens
Iris
Controls the size of pupil
Ciliary Body
Contains circular muscles that alter the shape of the lens during focusing
Lens
Gel like structure that helps focus the image
Vitreous Humour
Jelly like fluid filling the rear chamber of the eye, maintains eye shape
Blind Spot
Lacking cones and Rods
Optic Nerve
Transmits Impulses to the brain
Fovea
Region of the retina containing only cones
Retina
Photosensitive layer containing rods and cones
Choroid
Pigmented layer which absorbs light and prevents internal reflection
Sclera
Tough white fibrous layer protecting the eyeball and allows for attachment to external muscles
Suspensory Ligaments
Ligaments that attach lens to ciliary body
Rods (3)
- Found mainly in the peripheral parts of the retina
- Very sensitive to light - Work well in darkness
- Give info in Black and white
Cones (3)
- Found mainly packed together in the Fovea
- Less sensitive to light - Work well in bright light
- Three types of cones for 3 colours
In bright light (3)
Circular Muscles - Contract
Radial Muscles - Relaxes
Pupil - Constricts
In dim light (3)
Circular muscles - Relax
Radial Muscles - Contract
Pupil - Dilates
When looking at a distant object (3)
Ciliary muscles - relax
Ligaments - Tight
Lens - Long and thin
When looking at a close object (3)
Ciliary muscles - Contract
Ligaments - Slack
Lens - Short & Fat
