Chapter 3: Structures of the Eyes Flashcards
(42 cards)
The human eyeball sits in a protective, bony cavity called?
The orbit.
What does the eyelids and eyelashes protect?
The eye tissues.
Why does the blinking spreads a film of tears over the eyeball’s exposure surface?
To protect and lubricate the eye and sweep debris away.
What is The Conjunctiva?
A clear, thin mucous membrane that covers the inner surface of the eyelids and the back and sides of the eye’s outer surface.
What does The Conjunctiva do?
Keep the front surface of the eye moist and lubricated.
Why does The Conjunctiva keep the inner surface of the eyelids moist and lubricated?
So they open and close easily without friction or causing eye irritation.
What does the Conjunctiva protect the eye from?
From dust, debris and infection-causing microorganism.
What are the three layers that made up The Wall of the Eyelid?
Sclera, Choroid and Retina.
What is The Sclera?
The tough outer tissue that protects the entire eyeball.
The Sclera is also known as?
The White of the eye.
What is The Choroid?
The middle layer of the eye that contains the blood vessels that nourish the eye.
What is The Retina?
The innermost layer of light-sensitive tissue that lines the back of the eye.
The Retina converts light into what?
Into electrical impulses that travel through the optic nerve to the brain which interprets them as images.
The front one-third of the eye is divided into what?
Two chambers.
What is the Anterior chamber?
The front part of the eye between the cornea and the lens.
What is the Posterior Chamber?
Is between the iris and lens.
What fills most of the inside of the eye?
Fluid.
What are the chambers in front of the lens (anterior and posterior chambers) filled with?
With a clear, watery fluid called aqueous humor.
What does the large space behind the lens contain?
A thick, gel-like fluid called vitreous humor.
What are the two fluids that press against the inside of the eyeball and help it keep its shape?
Aqueous humor and Vitreous humor.
What is the Cornea?
A transparent, dome-shaped membrane.
Where is the Cornea located?
At the center of the front of the eye.
If the Cornea has no blood supply, from where does it obtains its nutrients?
From tears and from fluid in the anterior chamber behind it.
The cornea plays a key role in vision by helping what?
Focus the light that comes into the eye on the retina.