B3.1.3 - The eye Flashcards
What is the eye?
It is the sense organ that allow you to see
What is the cornea?
It is a transparent coating at the front which protects the eye by refracting light entering it
What is the pupil?
A central hole in the iris which allows light to enter
What is the iris?
A coloured ring of muscle tissue which alters pupil size by contracting or relaxing
What is the lens?
Transparent biconvex lens which focus light clearly onto the retina
What is the ciliary body?
A ring of muscle tissue which alters the shape of the lens
What are the suspensory ligaments
Ligament tissue which connect the ciliary muscle to the lens
What is the optic nerve?
Nervous tissue which carries nerve impulse to the brain
When your ciliary muscles contract…
your lens become more convex (fat) meaning you can focus on nearby objects
When your ciliary muscles relax…
your lens become less convex (thin) meaning you can focus on distant objects
What is short sightedness?
When distant objects are blurry
What is long sightedness?
When you cannot focus on nearby objects
What is short sightedness caused by?
The lens being too strong or eyeball being too long
What is long sightedness caused by?
The lens being too weak or eyeball being too short
What are the 2 types of photoreceptor cells in our retina?
Rods and Cones
