Special Senses: The Eyes and Ears

Comprehensive question-and-answer flashcards covering medical terminology, anatomical structures, physiological functions, and pathologies of the eyes and ears based on lecture notes.

Which combining forms are associated with the eyes?

opt/i, opt/o, optic/o, and ophthalm/o

Which combining forms refer to the iris?

ir/i, ir/o, irid/o, and irit/o

Which combining forms represent the lens of the eye?

phac/o and phak/o

What combining form refers to the retina?

retin/o

Which combining forms relate to the lacrimal apparatus?

dacryocyst/o and lacrim/o

Which combining forms refer to the ears?

acous/o, acoust/o, audi/o, audit/o, and ot/o

What combining form refers to the outer ear?

pinn/i

Which combining forms refer to the middle ear?

myring/o and tympan/o

What combining form refers to the inner ear?

labyrinth/o

According to the Joint Commission, what do the abbreviations OD, OS, and OU stand for?

OD stands for right eye (oculus dexter), OS stands for left eye (oculus sinister), and OU stands for each eye (oculus uterque) or both eyes (oculi uterque).

What is the adnexa of the eyes (adnexa oculi)?

The accessory or adjoining anatomical parts outside the eyeball, including the orbit, eye muscles, eyelids, eyelashes, conjunctiva, and lacrimal apparatus.

What is the orbit (eye socket)?

The bony cavity of the skull that contains and protects the eyeball and its associated muscles, blood vessels, and nerves.

What is the conjunctiva?

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.

How many major muscles are attached to each eye, and what are their names?

Six major muscles arranged in three pairs: superior and inferior oblique muscles, superior and inferior rectus muscles, and lateral and medial rectus muscles.

What is binocular vision?

Vision that occurs when the muscles of both eyes work together in coordination to make normal depth perception possible.

What is the canthus?

The angle where the upper and lower eyelids meet.

What is the tarsus (tarsal plate)?

The framework within the upper and lower eyelids that provides the necessary stiffness and shape.

Where are the lacrimal glands located, and what is their primary function?

They are located on the underside of the upper eyelid just above the outer corner of each eye and secrete lacrimal fluid (tears) to maintain moisture on the anterior surface of the eyeball.

What is the flow path of excess tears from the eyes to the nose?

Tears enter the lacrimal canal at the inner corner of each eye, empty into the lacrimal sac, and drain into the nose through the nasolacrimal duct (lacrimal duct).

What are the three layers that compose the wall of the eyeball?

The sclera, choroid, and retina.

What is the sclera and what is its role?

The tough, fibrous white outer layer of the eyeball that maintains the shape of the eye and protects the delicate inner layers of tissue (except the part covered by the cornea).

What is the choroid?

The opaque, middle layer of the eyeball that contains many blood vessels and provides the blood supply for the entire eye.

How are the anterior and posterior chambers of the anterior segment defined?

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.

What fluid fills the anterior segment, and how is it filtered and drained?

Aqueous humor (aqueous fluid), which is constantly filtered and drained through the trabecular meshwork and canal of Schlemm.

What is vitreous humor (vitreous gel)?

A soft, clear, jelly-like mass containing millions of fine fibers attached to the surface of the retina that fills the posterior two-thirds of the eyeball and helps maintain its shape.

What are the distinct visual receptor functions of retinal rods and cones?

Rods are black and white receptors, while cones are color receptors.

What is the macula (macula lutea)?

The clearly defined light-sensitive area in the center of the retina that is responsible for sharp central vision.

Why is color vision best in the fovea centralis?

Because it contains a high concentration of cones and contains no rods.

What is the optic disk (blind spot)?

A small region in the eye where nerve endings of the retina enter the optic nerve; it does not contain any rods or cones to convert images into nerve impulses.

Which three structures form the uvea?

The choroid, ciliary body, and iris.

How does the ciliary body adjust the lens to focus on nearby versus distant objects?

It adjusts the lens to make it thicker to focus on nearby objects, and stretches the lens to make it thinner to focus on distant objects.

How do the muscles of the iris regulate light entering the eye?

They contract to make the pupil opening smaller to decrease light, and relax/dilate to make the pupil opening larger to increase light.

What is the cornea?

The transparent outer surface of the eye covering the iris and pupil, serving as the primary structure focusing light rays entering the eye.

What is accommodation?

The process whereby the eyes make adjustments (including contraction, dilation, eye movement, and changes in lens shape) for seeing objects at various distances.

What is emmetropia?

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.

What distinguishes an ophthalmologist from an optometrist?

An ophthalmologist is a physician who specializes in diagnosing and treating the full spectrum of eye diseases and disorders, including eye surgery; an optometrist holds a Doctor of Optometry degree, provides primary eye care, diagnoses diseases, and prescribes corrective lenses.

What is ptosis (blepharoptosis)?

Drooping of the upper eyelid that is usually due to muscle weakness or paralysis.

What is the clinical difference between a chalazion and a hordeolum (stye)?

A chalazion is a nodule or cyst caused by obstruction of a sebaceous gland, whereas a hordeolum is a pus-filled and often painful lesion caused by an acute infection in a sebaceous gland.

What is the difference between ectropion and entropion?

Ectropion is the eversion (turning outward) of the edge of an eyelid, whereas entropion is the inversion (turning inward) of the edge of an eyelid causing eyelashes to rub against the cornea.

What is dacryoadenitis, and what are its symptoms?

An inflammation of the lacrimal gland caused by a bacterial, viral, or fungal infection; signs and symptoms include sudden severe pain, redness, and pressure above the eye.

What is dacryocystitis?

An inflammation of the lacrimal sac usually caused by blockage of the lacrimal duct, often accompanied by a bacterial infection.

What is a subconjunctival hemorrhage?

Bleeding between the conjunctiva and the sclera that creates a red area over the white of the eye, usually caused by an injury.