HOSA: Medical Terminology 2016 Chapter 11

eyelid

hearing

iris

horny, hard, cornea

tympanic membrane, eardrum

eye vision

vision condition

eye vision

ear, hearing

lens of eye

old age

retina, net

sclera, white of eye, hard

turn, change

tympanic membrane, eardrum

means the accessory or adjoining anatomical parts of an organ. The term adnexa is plural

also known as adnexa oculi, are the structures outside the eyeball. These include the orbit, eye muscles, eyelids, eyelashes, conjunctiva, and lacrimal apparatus

occurs when the muscles of both eyes work together in coordination to make normal depth perception possible. Depth perception is the ability to see things in three dimensions.

corner of the eye

angle where the upper and lower eye lids meet

which are small hairs, make up the eyebrows and eyelashes. Cilia are also present in the nose to prevent foreign matter from being inhaled.

also known as the tarsal plate, is the framework within the upper and lower eyelids that provides the necessary stiffness and shape
(tars means edge of the eyelid, and -us is a singular noun ending) (plural, tarsi). Note: Tarsus also refers to the seven tarsal bones of the foot’s instep.

edge of eyelid

is the transparent mucous membrane that lines the underside of each eyelid and continues to form a protective covering over the
exposed surface of the eyeball

also known as the nasolacrimal duct, is the passageway that drains excess tears into the nose.

consists of a duct at the inner corner of each eye. These ducts collect tears and empty them into the lacrimal sacs. Crying is the overflowing of tears from the lacrimal canals.

also known as the white of the eye, maintains the shape of the eye and protects the delicate inner layers of tissue. This tough, fibrous tissue forms the outer layer of the eye, except for the part covered by the cornea.Note: The combining formscler/o means the white of the eye, and it also means hard.

also known as the choroid coat, is the opaque middle layer of the eyeball that contains many blood vessels and provides the blood supply for the entire eye. Opaque means that light cannot pass through this substance.

the sensitive innermost layer that lines the posterior segment of the eye. The retina receives nerve impulses and transmits them to the brain via the optic nerve. This is also known as the second cranial nerve

The anterior chamber is located behind the cornea and in front of the iris. The posterior chamber is located behind the iris and in front of the ligaments holding the lens in place. Note: Don’t confuse the posterior chamber with the posterior segment

which is also known as aqueous fluid, fills both of these chambers. The term aqueous means watery or containing water. As used here, the term humor describes any clear body liquid or semifluid substance. n The aqueous humor helps the eye maintain its shape and nourishes the intraocular structures. This fluid is constantly filtered and drained through the trabecular meshwork and the canal of Schlemm

The posterior segment, which makes up the remaining two-thirds of the eyeball, is lined with the retina and filled with vitreous (VIT-ree-us) humor. Also known as vitreous gel, this is a soft, clear, jelly-like mass that contains millions of fine fibers. These fibers, which are attached to the surface of the retina, help the eye maintain its shape

of the retina receive images that have passed through the lens of the eye. These images are converted into nerve impulses and transmitted to the brain via the optic nerve. Rods are the black and white receptors, and cones are the color receptors.

also known as the macula lutea, is the clearly defined light-sensitive area in the center of the retina that is responsible for sharp central vision. Note that the term macula means a small spot. A macula, also known as a macule, can also refer to a small, discolored spot on the skin, such as a freckle

is a pit in the middle of the macula. Color vision is best in this area because it contains a high concentration of cones and no rods.

also known as the blind spot, is a small region in the eye where the nerve endings of the retina enter the optic nerve. This is called the blind spot, because it does not contain any rods or cones to convert images into nerve impulses.

is the pigmented layer of the eye. It has a rich blood supply and consists of the choroid, ciliary body, and iris

which is located within the choroid, is a set of muscles and suspensory ligaments that adjust the thickness of the lens to refine the focus of light rays on the retina (Figure 11.6). n The ciliary body produces the aqueous humor that fills the anterior segment of the eye. n To focus on nearby objects, these muscles adjust the lens to make it thicker. n To focus on distant objects, these muscles stretch the lens so it is thinner.

the colorful circular structure that surrounds the pupil (Figure 11.3). The muscles within the iris control the amount of light that is allowed to enter the eye through the pupil. n To decrease the amount of light entering the eye, the muscles of the iris contract, making the opening of the pupil smaller. n To increase the amount of light entering the eye, the muscles of the iris relax, or dilate, making the opening of the pupil larger. See dilation under the section on diagnostic procedures. Note that the term dilate refers to expanding any opening of the body, for example, the dilating pores of the skin or of the cervix during childbirth (see Chapter 14).

is the transparent outer surface of the eye covering the iris and pupil. It is the primary structure focusing light rays entering the eye

is the black circular opening in the center of | the iris that permits light to enter the eye.

is the process whereby the eyes make adjustments for seeing objects at various distances. These adjustments include contraction (narrowing) and dilation (widening) of the pupil, movement of the eyes, and changes in the shape of the lens.

is the simultaneous inward movement of the eyes toward each other. This occurs in an effort to maintain single binocular vision as an object comes nearer.

in proper measure

is the normal relationship between the refractive power of the eye and the shape of the eye that enables light rays to focus correctly on the retina

also refractive power, is the ability of the | lens to bend light rays so they focus on the retina.

is the ability to distinguish object details and shape at a distance. Acuity means sharpness

drooping or sagging

is a nodule or cyst, usually on the upper eyelid, caused by obstruction in a sebaceous gland (plural, chalazia). A chalazion is a type of granuloma (see Chapter 12). Compare with a hordeolum

turn

also known as a stye, | is a pus-filled and often painful lesion on the eyelid

tear

also known as pinkeye, is an inflammation of the conjunctiva that is usually caused by an infection or allergy (conjunctiv means conjunctiva, and -itis means inflammation).

is a condition in | which the pupils are unequal in size

is the loss of transparency of the lens that causes a progressive loss of visual clarity. The formation of most cataracts is associated with aging; however, this condition can be congenital or due to an injury or disease

dilation of the pupil

nipplelike

is an involuntary, constant, rhythmic movement of the eyeball that can be congenital or caused by a neurological injury or drug use

is the contraction of the pupil, normally in response to exposure to light, but also possibly due to the use of prescription or illegal drugs

is a gradually progressive condition in which the macula at the center of the retina is damaged, resulting in the loss of central vision, but not in total blindness (macul means spot, and -ar mean pertaining to) (Figure 11.8D). n Age-related macular degeneration occurs most frequently in older people and is the leading cause of legal blindness in those older than age 60. n Dry macular degeneration, which accounts for 90% of these cases, is caused by the slow deterioration of the cells of the macula.

is a group of diseases characterized by increased intraocular pressure that causes damage to the retinal nerve fibers and the optic nerve (Figure 11.8C). This increase in pressure is caused by a blockage in the flow of fluid out of the eye.this pressure can cause the loss of peripheral vision and eventually blindness.

inward

double

night blindness

cross eyed

opposite crosseyed

farsighted

nearsighted

eyes point in different directions

is a dimness of vision or the partial loss of sight, especially in one eye, without detectable disease of the eye (ambly means dim or dull, and -opia means vision condition).

also known as blind spot, is an abnormal area of diminished vision surrounded by an area of normal vision

carving

also known as the auricle or the outer ear, is the external portion of the ear. The pinna captures sound waves and transmits them into the external auditory canal.

transmits these sound waves | to the tympanic membrane (eardrum) of themiddle ear.

ear waxsecreted by ceruminous glands that line the auditory canal. This sticky yellow-brown substance has protective functions because it traps small insects, dust, debris, and some bacteria to prevent them from entering the middle ear.

which is located between the outer ear and the inner ear, transmits sound across the space between these two parts

also known as the eardrum, is located between the outer and middle ear (Figure 11.13). The word parts myring/o and tympan/o both mean tympanic membrane. When sound waves reach the eardrum, this membrane transmits the sound by vibrating.

is the temporal bone containing | hollow air space that surrounds the middle ear.

are three small bones located within the middle ear (Figure 11.12). The role of these bones is to transmit the sound waves from the eardrum to the inner ear by vibration. These bones are named for the Latin terms that describe their shapes

hammer

anvil

stirrup

The eustachian tubes (you-STAY-shun), also known as the auditory tubes, are narrow tubes that lead from the middle ear to the nasal cavity and the throat. The purpose of these tubes is to equalize the air pressure within the middle ear with that of the outside atmosphere.

contains the sensory receptors for hearing and balance. The structures of the inner ear are known as the labyrinth

which is located under the base of the stapes, is the membrane that separates the middle ear from the inner ear. Vibrations enter the inner ear through this structure.

is the snail-shaped structure of the inner ear and is where sound vibrations are converted into nerve impulses. Located within the cochlea are the cochlear duct, the organ of Corti, the semicircular canals, and the acoustic nerves. Cochlea comes from the Greek term for snail.

receives the vibrations from the cochlear duct and relays them to the auditory nerve fibers. These fibers transmit the sound impulses to the auditory center of the brain’s cerebral cortex, where they are heard and interpreted.

contain the liquid endolymph and sensitive hair-like cells. The bending of these hair-like cells in response to the movements of the head sets up impulses in nerve fibers to help maintain equilibrium. Equilibrium is the state of balance.

transmit this information to the brain, and the brain sends messages to muscles in all parts of the body to ensure that equilibrium is maintained. These nerves are discussed

is the process by which sound waves enter the ear through the pinna and then travel down the external auditory canal until they strike the tympanic membrane, which is located between the outer ear and middle ear.

occurs as the eardrum vibrates and causes the auditory ossicles of the middle ear to vibrate. The vibration of these bones transmits the sound waves through the middle ear to the oval window of the inner ear.

occurs when these sound vibrations reach the inner ear. The structures of the inner ear receive the sound waves and relay them to the auditory nerve for transmission to the brain.

fused together

fungus

is a sense of whirling, dizziness, and loss of balance that are often combined with nausea and vomiting. Although it is a symptom of many disorders, recurrent vertigo is sometimes associated with inner ear problems such as Ménière’s disease.

cholesterol

also commonly pronounced (TIN-uh-tus), is a condition of a ringing, buzzing, or roaring sound in one or both ears. It is often associated with hearing loss and is more likely to occur when there has been prolonged exposure to loud noises.