Eyes Flashcards
what are the eyelids?
//two movable shades //protect the eye from injury, strong light and dust
which eyelid is more mobile?
the upper
what are eyelashes?
//short hairs in double or triple rows that curve outward from the eyelid margins //filter out dust and dirt
what is the palpebral fissure?
//the elliptical open space between eyelids
what is the limbus?
the border between the cornea and sclera
what is the canthus?
//corner of the eye //angle where eyelids meet
what is the caruncle?
//at the inner canthus //is a small fleshy mass containing the sebaceous glands
with respect to the upper eyelid, where does a nurse expect to see it in relation to the iris?
when the eyes are open upper eyelid covers part of iris
where is the lower eyelid margin when the eye is open?
at the limbus (the border between cornea and sclera)
what are tarsal plates?
//strips of connective tissue that give shape to the upper eyelids
//contain meibomian glands
what are the meibomian glands?
//modified sebaceous glands the secrete oily lubricating material onto eyelids //the secretion stops tears from overflowing and helps eyelids to form an airtight seal when closed //located in the tarsal plates (connective tissue of upper eyelid)
what is the conjunctiva?
//a thin mucous membrane folded like an envelope between the eyelids and the eyeball
//transparent and covers the exposed part of the eye
what is the palpebral conjunctiva?
//lines eyelids //clear with many small blood vessels //forms a deep recess and then folds back over eye
what is the bulbar conjunctiva?
//overlies eyeball //is clear, but white sclera shows through it
where does the conjunctiva merge with the cornea?
at the limbus
what does the lacrimal apparatus do?
provides constant irrigation to keep conjunctiva and cornea moist and lubricated
what makes tears?
lacrimal glands
what is the path of tears?
tears wash across the eye and are drawn up evenly as the eye blinks
drain into puncta, then nasolacrimal sac through the nasolacrimal duct emptying into the inferior meatus inside the nose
what are punctum?
there is a superior and inferior puncta
are located just above and just below carnucle (a interior corners of eyes)
how many muscles attach the eyeball?
six
what are the six muscles that attach the eyeball (extraocular muscles)?
superior rectus inferior rectus lateral rectus medial rectus superior oblique inferior oblique
what is the function of the six muscles attached to the eyeball?
direct eye to area of person’s interest
//enable both straight and rotary movement
//each muscle is yoked with one in the other eye so that the two eyes move with axes always parallel (conjugate movement)
what is conjugate movement?
yoking of muscles that move eyeball (extraocular muscles) causes them to move with axes always parallel, this is conjugate movement