structure and function Flashcards
It transmits visual stimuli to the brain for interpretation and function as the organ of vision.
eye
located in the eye orbit, a round, bony hollow formed by several different bones of the skull.
eyeball
in the ____ a cushion of fats surrounds the eye.
orbit
these protects the eyeball
bony orbit and fat cushion
are two movable structures composed by skin
eyelids
what are the two types of eyelids.
striated and smooth
their purpose is to protect the EU from foreign bodies and limit the amount of light following the eye
striated and smooth eyelids
the upper eyelid is larger, more mobile and contains ___ made up of connective tissue
tarsal plates
tarsal plates contain the ___ which secrete and oily substance that lubricate the eyelid
meibomian glands
they serve to distribute tears that lubricate the surface of the eye.
striated and smooth eyelids
the eyelids joined at two points, what are these?
lateral(outer) canthus and medial(inner) canthus
the medial canthus contains the ___ two small openings that allows drainage of tears into the lacrimal system
puncta
a small fleshy mass that contains sebaceous gland
caruncle
the white space between the open eyelid is called what?
palpebral fissure
the point where the sclera meets the cornea
corneal limbus
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, cutaneous membrane.
conjunctiva
what are the two portions of conjunctiva?
palpebral and bulbar portion
it lines the inside of the eyelid.
palpebral conjunctiva
cover most of the anterior eye, merging with the cornea at the limbus.
bulbar conjunctiva
consist of glands and ducts that lubricate the eye
lacrimal apparatus
located in the upper outer corner of the orbital cavity just above the eye, produces tears.
lacrimal gland
as the lid blinks, tears wash across the eye then drain into the ___ which are visible on the upper and lower limbs at the inner canthus.
puncta
tears empty into the ____ snd are then channeled into the ___ through the ____
lacrimal canals, nasolacrimal sac, nasolacrimal duct
tears drain into the ____
nasal meatus
the ____ are the six muscles attached to the outer surface of the eyeball
extraocular muscle
what are the four rectus muscles?
superior, inferior, lateral and medial
what are the two oblique muscles that are responsible for moving the eye in the direction controlled by that muscle
superior and inferior
these muscles allow for parallel movements of the eyes and thus the binocular vision characteristics of humans.
extraocular muscle
these muscles are supplied by three cranial nerve
oculomotor, trochlear and abducens
it is composed of three separate costs or layers
eyeball
what are the external layers of the eye?
sclera and cornea
is a dense, protective, white covering that physically supports the internal structures of the eye.
sclera
it permits the entrance of the light, which passes through the lens to the retina
cornea
it is continuous anteriorly with transparent cornea( the window of the eye)
sclera
it is well supplied with nerve endings, making it responsive to pain and touch
cornea
because of this sensory property, contact with a wisp of cotton stimulates a blink in both eyes known as the ____
corneal reflex
the middle layer, consist both an anterior portion, which includes the _____ and ____. and a posterior layer which includes the ____
iris and the ciliary body. choroid
consist of muscle tissue that controls the thickness of the lens, which must be adopted to focus on objects near and far away.
cilliary body
circular disc of muscle containing pigments that determines eye color
iris
it is the central aperture of the iris.
pupil
a biconvex, transparent, avascular, encapsulated, structure located immediately posterior to the iris.
lens
attached to the cilliary body supports the position of the lens
suspensory ligaments
