15d

Aqueous humor

________ is a fluid tha circulates within the anterior cavity, passing from the posterior to the anterior chamber through the pupil; it also freely diffuses through the vitreous body and across the surface of the retina, where it is called vitreous humor

Conjunctivitis

__________, or pinkeye, is an inflammation of the conjunctiva; the most obvious sign, redness, is due to the dilation of bood vessesl deep to the conjunctival epithelium

Laser assisted in situ keratomileusis

a variation on PRK is _________; in this procedure the interior layers of the cornea are reshaped and covered by a flap of normal cornea epithelium; roughly 10% of _______ patients achieve normal vision

Scleral venous isnus

aqueous humor leaves the eye through the _________, a passageway that extends completely around the eye at the level of the corneal limbus; collecting channels deliver the aqueous humor form this canal to veins in the sclera

Close vision

ciliary muscle contracted, lens rounded

Distant vision

ciliary muscle relaxed, lens flattened

Optic radiation

form each lateral geniculate nucleus, visual information travels to the occipital cortex of the cerebral hemisphere on that side; the bundle of projection fibers linking each lateral geniculate nucleus with the visual cortex is known as the __________

Moyopia

if the eyeball is too deep or the resting curvature of the lens is too great, the image of a distant object is projected in front of the ertina; such individuals are said to be nearsighted because vision at close range is clear, but distant objects are blurry and out of focus

Hyperopia

if the eyeball is too shallow or the lens too flat, _______ results; the ciliary muscle must contract to focus even a distant object on the retina, and at close ragne the lens cannot provide enough refraction to focus an image on the retina; ______ people are said to be farshighted because they can see distant object most clearly

Emmetropia

in the normal healthy eye, when the ciliary muscle is relaxed and the lens is flattened, the image of a distant object will be focused on the retina's surface; this condition is called _________

Lysozyme

lacrimal gland secretions contain the antibacterial enzyme _________ and antibodies that attack pathogens before they enter the body

Refracted

light is _________ or bend, when it passes from one medium to another medium with a different density

Medial canthus

medially, the two eyelids are connected at the _________

Tarsal glands

modified sebaceous glands called ________, or Meibomian glands, are along the inner margin of the lid; these glands secrete a lipid-rich product that helps keep the eyelids from sticking together

Vitreous body

most of the posterior cavity's volume is taken up by a gelatinous substance known as the ________

Ciliary processes

the ________ are folds of epithelium covering the ciliary muscle

Lacrimal canaliculi

the ________ are small canals that connect the lacrimal puncta to the lacrimal sac

Optic nerve

the ________ carries visual information to the brain

Pupillary dilator muscles

the ________ extend radially away from the edge of the pupil; contraction of these muscles enlarges the pupil

Posterior chamber

the ________ extends between the iris and the ciliary body and lens

Pupillary constrictor muscles

the ________ form a series of concentric circles around the pupil; when these sphincter muscles contract, the diameter of the pupil decreases

Lacrimal sac

the ________ is a small chamber that nestles within the lacrimal sulcus of the orbit

Choroid

the ________ is a vascular layer that is covered by the sclera; the __________ has an extensive capillary network that delivers oxygen and nutrients to the neural tissue within the neural layer

Inner layer/ retina

the ________ is the innermost layer of the eye; the ______ consists of a thin outer layer that absorbs light, and a thick inner layer that contains the photoreceptors

Visual axis

the ________ of the eye is an imaginary line drawn from the center of an object your are looking at directly, through the center of the cornea of the lens to the retina

Nasolacrimal duct

the ________ originates at the inferior tip of the lacrimal sac; it passes through the nasolacrimal canal to deliver tears to the nasal cavity

Lacrimal apparatus

the ________ produces, distributes, and removes tears; the _____ of each eye consists of a lacrimal gland with associated ducts, paired lacrimal canaliculi, a lacrimal sac, and a nasolacrimal duct

Lacrimal puncta

the _________ are two small pores that drain the lacrimal lake

Ocular conjunctiva

the _________ covers the anterior surface of the eye

Palpebral conjunctiva

the _________ covers the inner surface of the eyelids

Anterior chamber

the _________ extends from the cornea to the iris

Pigmented part of the retina

the __________ absorbs light that passes through the neural part, preventing light from bouncing and and producing visual echones

Vascular layer/ uvea

the __________ contains numerous blood vessels, lymphatic vessels, and the intrinsic muscles of the eye; the functions include (1) providing a route for blood vessels and lymphatics that supply tissues of the eye; (2) regulating the amount of light that enters the eye; (3) secreting and reabsorbing the fluid called aqueous humor that circulates within the chambers of the eye, and (4) controlling the shape of the lens

Ciliary body

the __________ is a thickened region that bulges into the interior of the eye; suspensory ligaments extend from the _______ to the lens, holding it in position posterior to the pupil

Ora serrata

the ___________ is the jagged anterior edge of the neural part of the retina; the outer pigmented part of the retina continues anteriorly across the posterior surface of the iris

Depth perception

the ability to judge depth or distance by interpreting three dimensational relationships among objects in view

Lacrimal gland

the almond shaped _________ is about 12-20 mm long; each day it produces about 1 mL of waterly, slightly alkaline tears; the tears lubricate, nourish, and oxygenate the corneal cells

Ciliary muscle

the bulk of the ciliary body consists of the _________, a smooth muscular ring that projejcts into the interior of the eye

Photoreceptors

the cells that are sensitive to light

Fovea centralis

the central area at the center of the macula with the higheste concentration of photoreceptors is called the _________; when you look directly at an object, its image falls on this portion of the retina

Iris

the colored _________ is visible through the transparent cornela surface; it contains blood vessels, pigment cells, and layers of smooth muscle fibers; when these muscles contract, they change the diameter of the pupil

Focal distance

the distance between the lens and its focal point is the _________ of the lens

Conjunctiva

the epithelium covering the inner and outer surfaces of the eyelids and the outer surface of the eye is called the ________; it is a mucous membrane covered by a specialized stratified squamous epithelium

Palpebral

the eyelid, or _________, is a continuation of the skin; the continual blinking of the __________ keeps the surface of the eye lubricated, and removes dust and debris; the eyelids can also close firmly to protect the delicate surface of the eye

Ciliary zonule

the fibers making up the ________ attach to the tips of the ciliary processes; these connective tissue fibers hold the lens posterior to the iris and centered on the pupil; as a result, light passing through the pupil will also pass through the lens

Palbera fissure

the gap that separates the free margins of the upper and lower eyelids

Near point of vision

the inner limit of clear vision, known as the ________, is determined by the degree of elasticity of the lens; children can usually focus on something 3-4 inches from the eye, but over time the lens tends to become stiffer and less responsive

Crystallins

the lens consists of concentric layers of cells surrounded by a desnse fibrous capsule; the cells are slender, long, and filled with transparent proteins called __________, which are responsible for both the clarity and the focusing power of the lens

Fibrous layer

the outermost layer of the eye, consists of the cornea and the white sclera

Fornix

the pocket created where the palpebral conjunctive becomes continuous with the ocular conjunctiva is known as the _______ of the eye

Tonometry

the procedure that measures the eye's intraocular pressure, the fluid pressure within the anterior chamber

Focal point

the specific point of intersection on the retina

Corneal limbus

the two components are continuous and the border between the two is called the _________

Optic chiasm

the two optic nerves, one from each eye, reach the diencephalon at the _________

Macula

the very highest concentration of photoreceptors occurs at the center of an area called the ________ or macula lutea

Sclera

the white of the eye, outermost layer

Tear ducts

there are 10-12 _______ that deliver tears from the lacrimal gland to the space behind the upper eyelid

Photoreactive keratectomy

variable success at correcting myopia and hyperopia has been achieved by surgery that reshapes the cornea; in _________ a computer guided laser shapes the cornea to exact specifications; tissue is removed to only a debth of 10-20 um, no more than 10% of the cornea's thickness; the entire procedure can be done in less than a minute

Accommodation

we focus images on the retina by changing the shape of the lens to keep the focal distance constant and give us clear vision, a process called ________