eyes
protect the eyeball?
-bony orbit
-fat cushion
eye transmits?
-visual stimuli to the brain for interpretation
-doing so, functions as the organ of vision
eyeball is located?
eye orbit
are two movable structures composed of skin and two types of muscle
eyelids (upper and lower)
two types of muscle in the eyelids
-striated
-smooth
purpose of eyelid?
- is to protect the eye from foreign bodies
- limit the amount of light entering the eye
- serve to distribute tears that lubricate the surface of the eye
is larger, more mobile, and contains tarsal plates made up of connective tissue.
upper eyelid
tarsal plates made up of?
connective tissue
upper eyelid contains _______________ that made up of connective tissue
tarsal plate
tarsal plate contains?
meibomian glands
meibomian glands?
secrete an oily substance that lubricates the eyelid.
eyelids join at two points:
-the lateral (outer) canthus
-medial (inner) canthus
medial canthus contains the?
puncta
puncta?
two small openings that allow drainage of tears into the lacrimal system
caruncle?
a small, fleshy mass that contains sebaceous glands
white space between open eyelids is called the _____________
palpebral fissure
are projections of stiff hair curving outward along the margins of the eyelids that filter dust and dirt from air entering the eye
eyelashes
is a thin, transparent, continuous membrane that is divided into two portions
conjunctiva
two portions of conjunctiva:
a palpebral and a bulbar portion
lines the inside of the eyelids
palpebral conjunctiva
covers most of the anterior eye, merging with the cornea at the limbus
bulbar conjunctiva
The _________________ consists of glands and ducts that lubricate the eye
lacrimal apparatus
The lacrimal apparatus consists of _______ and ________ that lubricate the eye
glands and ducts (tears)
lacrimal gland, located in the ___________________
upper outer corner of the orbital cavity just above the eye, produces tears
are the six muscles attached to the outer surface of each eyeball
extraocular muscles
four rectus muscles:
-superior rectus
-inferior rectus
-lateral rectus
-medial rectus
two oblique muscles:
-superior oblique
-inferior oblique
Innervation for these muscles is supplied by three cranial nerves:
-oculomotor (III)
-trochlear (IV)
-abducens (VI)
Extraocular muscles control the _______________________
direction of eye movement
eyeball is composed of three separate coats or layers:
-external layer
-middle layer
-inner layer
The external layer consists of the ______________
-sclera
-cornea
is a dense, protective, white covering that physically supports the internal structures of the eye.
sclera
It is continuous anteriorly with the transparent _____________ (the “window of the eye”).
cornea