objective 9 Flashcards
(90 cards)
protect the eye from injury.
eyelids
larger and more mobile
upper eyelids
filter out dust and dirt
eyelashes
elliptical open space between the eyelids
palpebral fissure
the eyelids margins approximate completely
when the eyes are closed
the upper eyelid covers part of the iris. the lower eyelid margin is just at the limbus
when the eyes are open
boarder between the cornea and sclera
limbus
the corner of the eye, angle where the eyelids meet
canthus
a small fleshy mass that contains sebaceous glands
caruncle
strips of connective tissue that give the eyelid shape. they are located in the upper eyelid
tarsal plates
contained in the tarsal plates, they secrete an oily lubricating material onto eyelids
meibomian glands
transparent protective covering on the exposed part of the eye
conjunctiva
provides constant irrigation to keep the conjunctiva and cornea moist and lubricated
lacrimal apparatus
where the tears drain into
puncta
how many eye muscles are there?
6
tough protective white covering that is continuous anteriorly with the cornera
outer fibrous sclera
transparent and covers iris and pupil
cornea
has dark pigmentation to prevent light from reflecting
internally and is heavily vascularized to deliver blood to the retina
choroid
controls the amount of light admitted into the retina
iris
size determined by a balance of the parasympathetic and sympathetic chains of the autonomic nervous system
pupil
serves as a refracting medium, keeps a viewed object in constant focus on retina
lens
contains fluid that continuously flows
anterior chamber and posterior chambers
visual receptor of the eye which light waves are changed into nerve impulses
retina
area in which fibers from the retina converge to form the optic nerve
optic disc