Jarvis Chapter 14 Eyes Flashcards
eyelids
two movableshades that further protect the eye from injury, strong light, and dust
palpebral fissure
the elliptical open space between the eyelids
limbus
the border between the cornea and the sclera
canthus
the corner of the eye, the angle where the lids meet.
caruncle
found in the medial canthus, it is a small fleshy mass containing sebacceous glands
tarsal plates
found within the upper lid, these strips of connective tissue that give it shape. contain meibomian glands
meibomian glands
modified sebacceous glands that secrete an oily lubricating material onto the lids. this stops tears from overflowing and helps to form an airtight seal when the eyelids are closed. conatined by the tarsal plates
conjunctiva
the transparent protective covering over the exposed part of the eye. a thin mucus membrane folded like an envelop between the eyelids and eyeball.
palpebral conjunctiva
the thin mucous membrane that specifically lines the lids and is clear with many small blood vessels
bulbar conjunctivea
a thin mucous membrane that overlayes the eyeball, with the white sclera showing through. at the limbus the conjunctiva merges with the cornea
lacrimal apparatus
the provider of constant irrigation to keep the conjunctiva and cornea moist and lubricated. lacrimal gland, puncta, nasolacrimal sac, nasolacrimal duct, inferior meatus
rectus
the extraocular muscles that are straight. there are four muscles: superior, inferior, lateral, and medial
oblique
the two extraocular muscles that provide rotary movement: superior and inferior
Cranial Nerve VI
the abducens nerve which innervates the lateral rectus muscle (abducts the eye)
Cranial Nerve IV
the trochlear nerve which innervates the superior oblique muscle
Cranial Nerve III
the oculomotor nerve. innervates all the rext (superior, ingerior and medial rectus and the inferior oblique muscles
sclera
the outer fibrous layer of the eye. a tough, protective white covering
choroid
the middle vascular layer of the eye which has dark pigmentation to prevent light from reflecting internally and is heavily vascularized to deliver blood to the retina. this layer is ontinuous with the ciliary body (control the thickness of the lens) and the iris (functions as a diaphragm, varying the opening at its center and controls the amount of light admitted into the retina
retina
the inner nervous layer of the eye. This visual receptive layer of the eye changes light waves into nerve impulses. these impulses are conducted through the optic nerve and the optic tract to the cisual cortex of the occipital lobe. the image formed on this area of the eye is upside down and inversed form its actual appearance in the outside world.
cornea
continuous anteriorly with the sclera, which covers the iris and the pupil. it is part of the refracting media of the eye, bending incoming light rays so they will be focused on the inner retina. this is very sensitive to touch, contact with anything will stimulate a blink in both eyes
pupil
round and regular. its size is determined by a balance between the para/sympathetic chains of the autonomic nervous system
lens
a biconvex disc located just posterior to the pupil. serves as a refracting medium keeping a viewed object in continual focus on the retina
anterior chamber
posterior to the cornea and in front of the iris and lens. contains aqueous humor that is produced continually by the ciliary body. this continual flow of fluid serves to deliver nutrients to the surrounding tissues to drain metabolic wastes
optic disc
the area in which fibers from the retina converge to form the optic nerve