The Eye Flashcards
Draw a diagram of the eye
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Name the parts of the eye
Sciera, Choroid, Retina, Fovea, Optic nerve, Blind spot, Arteries and veins, Vitreous humour, External muscle, Conjuntiva, Cornea, Aqueous humour, Pupil, Lens, Iris, Ciliary muscle, Suspensory ligaments
What is the function of the eyelid?
Eyelids can cover and protect the eyes.
What is the function of the conjunctiva?
A thin transparent lining protecting the cornea.
What is the function of the cornea?
Front transparent part of the sclera. It focuses light rays on the retina.
What is the function of the sclera?
A tough fibrous outer layer - the “white” of the eye; it maintains the shape of the eyeball.
What is the function of the choroid?
The choroid contains blood vessels supplying food and oxygen to the cells of the eye.
What is the function of the retina?
The innermost layer that contains the receptor cells [rods and cones].
What is the function of the fovea?
The fovea is where our best vision is [mainly cones]
Where is the iris?
The front region of the choroid is specialised into the iris
What is the function of the iris?
The iris contains blood vessels and melanin [giving us out eye colour], and controls the amount of light entering the eye [through the pupil].
What happens to the pupil in bright light?
Pupil constricts
What happens to the pupil in dim light?
Pupil dilates
What is the function of the ciliary [muscle]?
Thickened edge of the choroid that controls the shape of the lens.
What is the function of the suspensory ligaments?
Holds the lens in place.
What is the function of the lens?
Like a magnifying glass, it focuses the light rays on the retina.
What is the function of the lens?
The lens focuses the light rays on the retina
What is accomodation?
Accommodation is the ability of the lens to change its shape (focal length) to form a clear image.
Draw a diagram of forming an image on the retina?
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How does the eye see distant objects?
For distant objects the ciliary muscle relaxes and so the suspensory ligaments pull tight, pulling the lens thinner - the light doesn’t bend as much
How does the eye see close objects?
For close objects the ciliary muscle contracts allowing the lens to go fat, thus bending the light more.
What is the function of the aqueous humour?
Watery liquid that supplies the lens and cornea with nutrients and helps keep the shape of the cornea and lens.
What is the function of the vitreous humour?
A gel that helps maintain the shape of the eye.
What happens when light rays focus on the retina?
Receptor cells are stimulated and impulses are carried along the optic nerve to the brain.
What is the function of the blind spot?
Where the optic nerve fibres pass through the retina and there is no room for receptors.
Name an eye defect
Long-sighted/short sighted
What does long-sighted mean?
You are long-sighted if you can clearly see objects a long way off, but you cannot see things close by.
What glasses can correct long-sightedness?
Reading glasses [convex lenses] can correct the problem.
Draw a diagram of long sight (and its correction)
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What does short-sighted mean?
You are short-sighted if you can clearly see objects close to you, but you cannot see things in the distance.
What glasses can correct short-sightedness?
Glasses with concave lenses can correct the problem
Draw a diagram of short-sighted (and it’s correction)
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