The Eye Flashcards
What is the cornea?
the transparent coating on the front of the eye
what is the function of the cornea?
it protects the eye as well as refracts light entering the eye
What is the pupil?
central hole in the iris
What is the function of the pupil?
it allows light to enter the eye
What is the iris?
a coloured ring of muscle tissue
What is the function of the iris?
it alters the size of the pupil by contracting or relaxing
What is the ciliary body?
ring of muscle tissue
What does the ciliary body do?
alters the shape of the lens
What are the suspensory ligaments?
ligament tissues in the eye
What is the function of the suspensory ligaments?
connects the ciliary muscle to the lens
How does the eye form an image when light enters it?
The cornea refracts incoming light rays and focusses most of the incoming light. The light then passes through the pupil and is further refracted by the lens. This creates a sharp image on the retina. Photoreceptors in the retina produce a nervous impulse when exposed to light. The impulse travels down the optic nerve to the brain, which interprets the impulses as a visual image.
How does the eye focus on nearby and distance objects?
by changing the shape of the lens
When the ciliary muscle contracts…
…the lens becomes more convex and you can focus on nearby objects
When the ciliary muscle relaxes…
…the lens becomes less convex and you can focus on distant objects
What is short-sightedness?
When distant objects are blurry
