The Eye Flashcards
What is the stimulus?
Light.
What is the receiver?
Eye.
What is the transformer?
Retina.
What is the conductor?
Optic Nerve.
What is the analyzer?
Brain.
Light behaves as 2 things? Name them.
1-Particles (photons)
2-waves (electromagnetic waves)
Do all waves pass through a medium?
Not all of them but yes some of them. The sun is an example of a wave that doesn’t pass through a medium.
What is the cornea?
The transparent part that bulges in front of the iris and pupil and is the continuity of the sclera.
What does the cornea do?
It allows light to go into the eye.
What is the aqueous humour?
A jelly in between the cornea and the iris.
What does the aqueous humour do?
It maintains a constant pressure in the eye and allows light through.
What is the iris?
The coloured part of the eye.
What does the iris do?
It adjusts the amount of light going on the retina.
What does the iris do when theres more light?
It opens up, (expands outwards and becomes bigger).
What is the pupil?
The hole in the eye.
What does the pupil do?
It allows light through.
What is the lens?
It contracts and extends depending on the distance of the object t focus on it.
What does the lens do?
It flips the light and focuses it on the retina.
What is the vitreous humour?
A jelly in between the lens and the retina.
What does the vitreous humour do?
It allows light through.
What is the retina?
Its where the light/image focuses on.
What light sensitive highly specialized cells are on the retina?
Rods and cones.
What are rods and cones?
The receptors/transformer.
What do rods and cones do?
They transform light and images into nerve impulses.
What is the choroid?
Its the continued part of the iris.
Describe the choroid. (2 things)
1-Under/behind the retina
2-Black
What is the choroid made up of?
Blood vessels that supply nutrients and oxygen to the eye.
What is the sclera?
The white tough surface of the eye except the cornea.
What does the sclera do?
It protects the eye from major impacts.
What is the optic nerve?
A wire like thing that sends the nerve impulses to the brain.
Where is the blind spot?
Its where the optic nerve begins.
Where is the fovea?
The back and center of the retina.
The ____ half of the field of vision is perceived by the right cerebral hemisphere.
Left.
What is refraction?
It’s when light travels at different speeds through different media.
Depending on the type of lens, what happens to the light when it goes through the lens?
It is bent.
In a normal eye where is the image/light focused?
On the retina.
How do we see?
The image/light gets flipped onto the retina when it goes through the lens, then gets flipped back upright by our brain.
Whats the scientific term for nearsightedness?
Myopia
Whats the scientific term for farsightedness?
Hyperopia
Myopic people can see______.
Near
Farsighted people can see_____.
Far
Myopia: The light focuses too near so the image is formed where?
In front of the retina.
Myopia: Why is the image in front of the retina? (Name 3 things)
The eyeball is too long, the lens is too thick, or strong ciliary muscles.
How can you correct the vision of a myopic person?
A concave lens.
Hyperopia: The light focuses too far so the image is formed where?
Behind the retina.
Hyperopia: Why is the image behind the retina? (Name 3 things)
The eyeball is too short, the lens is too thin, or weak ciliary muscles.
How can you correct the vision of a farsighted person?
A convex lens.
What is presbyopia?
The same as hyperopia except its due to aging.
What happens with presbyopia?
The lens loses its elasticity and cant bend the light as much therefore it focuses beyond the retina.
