Eyes Flashcards
Are projections of stiff hair curving outward along the margins of the eyelids that filter dust and dirt from air entering the eye.
EYELASHES
Are two movable structures composed of the skin and two types of muscle: striated and smooth.
The purpose is to protect the eyes from foreign bodies and limit the amount of light entering the eye.
They serve to distribute tears that lubricate the surface of the eye.
EYELIDS
The point where the 2 eyelids join.
Lateral and Medial
CANTHUS
Is a dense, protective, white covering that physically supports the internal structures of the eye.
It is continuous anteriorly with the transparent cornea (the windows of the eye).
Sclera
A thin, transparent, continuous membrane that is divided into two portions: PALPEBRAL&BULBAR
CONJUNCTIVA
lines the inside of the eyelids
Palpebral
Covers most of the anterior eye, merging with the cornea at the limbus.
BULBAR
Permits the entrance of light, which passes through the lens to the retina.
Supplied with nerve endings making it responsive to pain and touch.
CORNEA
External Structures of the Eye
Eyelashes
Eyelids
Canthus
Sclera
CONJUNCTIVA
CORNEA
A circular disc of muscle containing pigments that determine the eye color.
Muscles in the iris adjust to the control of the pupil’s size which controls the amount of
light entering the eye.
The muscle fiber of the iris also decreases the size of the pupil to accommodate for near
vision and dilate the pupil for far vision.
Iris
Is a biconvex, transparent, avascular structure located immediately posterior to the iris that functions to refract (bend) light rays onto the retina.
Lens
Consists of muscle tissue that controls the thickness of the lens, which must be adapted to focus on objects near and far away
Ciliary Body
Innermost layer that receives visual stimuli and send it to the brain.
Consists of numerous layers of nerve cells (rods and cones – called photoreceptors
because they are responsive to light).
RETINA
are sensitive to light, regulate black & white vision & function in dim light.
Rods
function in bright light and are sensitive to color.
Cones
Vascular necessary for the nourishment to the inner aspect of the eye and prevents light
reflecting internally.
Anteriorly continuous with the ciliary body and the iris.
Choroid
A cream colored, circular area located on the retina toward the medial or nasal side of the
eye.
It is where the optic nerve enters the eyeball.
Optic Disc
- Serve to maintain structure
- Protect against injury
- Transmit light rays
Chambers
located between the cornea and the iris
Anterior Chamber
located between the iris and the lens
Posterior Chamber
- A clear liquid substance produced by the ciliary body
- Helps to cleanse and nourish the cornea and lens
- Maintains intraocular pressure
Aqueous humor
Consists of glands and ducts that serve to lubricate the eye.
LACRIMAL APPARATUS
Two small openings that allow drainage of tears into the lacrimal system.
Puncta
A small fleshy mass that contains sebaceous glands.
Caruncle