| A | B |
|---|
| Sclera | a tough fiberous tissue of eye - the outward layer (White part) |
| Conjunctiva | a membrane that lines the eyelid and is reflected onto the eyeball |
| Choroid | The highly vascular middle layer of the eyeball. It provides blood supply for the entire eye. |
| Retina | The inner most layer of the eye. composed of nerve endings that are responsible for the reception and transmission of light impulses. |
| Cornea | the transparent portion of the sclera which allows light to enter the interior of the eye. |
| Lens | a crystalline structure held between the ciliary body and suspensory ligaments. |
| Ciliary body | thich part of a vascular membrane joining the iris and choroid of the eye. |
| Suspensory ligaments | the ligaments that hold the lens in place. |
| Accommodations | the process by which the muscles contract or relax and alter the shape of the lens, making it thicker or thinner - enabling light rays to focus on the retina. |
| Aqueous humor | One of the two major fluids of the eye. It provides nourishment for the lens and cornea. |
| Anterior cavity | Where the aqueous humor is found. |
| canal of Schlemm | the aqueous humor is drained from the eye by a small opening. |
| Pupil | The perforated center of the iris |
| Iris | A colored contractile membrane, which functions as a sphincter. |
| vitreous humor | The second major humor of the eye. A jellylike substance that fills the entire vitreous chamber. It is one of the refractive structures of the eye. |
| Vitreous chamber | Where the vitreous humor is found. |
| Rods and cones | The two visual receptors of the retina. Rods function in dim lught to produce black and white vision. Cones function in bright light and produce color vision. |
| Fovea | The center of the retina. All its receptors are cones. It provides the greatest acuity for color vision. |
| Photopigments | Rods and cones contain chemicals called photopigments. |
| Optic Nerve | One of a pair of sensory nerves, that arise in the retina and transmit visual impulses from the eye to the visual cortex of the brain. |
| Blind spot | Normal gap in the visual field, the result of a spot on the retina insensitive to light and located where the optic nerve enters the eye. |
| Optic disc | Both the optic nerve and blood vessels of the eye enter the eyeball at the optic disc. |
| conjunctiva | A thin mucous membrane that lines the inner surface of the eyelids and the cornea. |
| Lacrimal glands | lying superior and to the outer edge of each eye and produce tears that bathe and lubricate the eyes. |
| Canthi | The tears collect at the inner edges of the eyes (Canthus is plural). |
| Lacrimal canals | The canal tears pass through. They are pinpoint openings that lead to the nasal cavity. |
| External ear | The outer ear. One of three major sections. |
| Tympanic cavity | The middle ear. |
| Labyrinth | The inner ear. |
| Auricle | Collects waves traveling through air and channels them to the ear canal. |
| Pinna | Another term for the Auricle |
| External auditory meatus | The ear canal. (a slender tube) |
| Cerumen | Waxy secretion of the ear canal. |
| Tympanic membrane | Eardrum or tympanum |
| Malleus | Hammer. One of the 3 tiny articulating bones. |
| Incus | Anvil. One of the ossicles |
| Stapes | Stirrups. One of the ossicles. |
| Cochlea | These ossicles form a chain that stretches from the inner surface of the tympanum to a snail-shaped structure located in the inner ear. It is filled with fluid. |
| Hairs of corti | Lining the cochlea are tiny nerve endings called the hairs of corti. |
| Oval window | A membrane-covered opening on the external surface of the cochlea . |
| Eustachian tube | This tube connects the middle ear to the pharnyx. Its purpose is to equalize pressure on the outer and inner surface of the eardrum. |
| Semicurcular canals | Any of the three bony, fluid filled loops in the osseous labyrinth of the inner ear, concerned with the sense and maintenance of balance. |
| Vestibule | Space at the entrance to a hallow organ or passageway. |
| Static equilibrium | The orientation of the body relative to gravity. It allows one to maintain posture and orientation while at rest. |
| Dynamic equilibrium | Refers to maintaining body position in response to movement. |
| Ametropia | An error of refraction that exist when light rays fail to focus sharply on the retina. |
| Myopia | Nearsightedness |
| Hyperopia | Farsightedness |
| Presbyopia | A form of farsightedness- a defect assoc. with the aging process. |
| Astigmatism | The cornea or lens has a defective curvature. This causes light rays to diffuse over a large area of the retina, rather than being focused sharply on a given point. |
| Cataracts | Opacities that form on the lens or on the capsule containing the lens. |
| Cryoprobe | A super cooled metal probe for removing cataracts. |
| Intracapsular extraction | Removal of cataract and lens with a cryoprobe. |
| Senescent or senile cataract | A cataract that develops as a result of old age. |
| Extracapsular extraction | When both the cortex and lens are removed, but the posterior lens capsule is retained. This is in children and young adults. |
